refs #568: attempt to hint to Swift compiler about singleton constructor

@@ -32,9 +32,13 @@
 
 /** @name Accessing the Configuration */
 
+/** Access the shared instance of the configuration.
+*   @return The shared configuration instance. */
++ (instancetype)sharedInstance;
+
 /** Access the shared instance of the configuration. 
 *   @return The shared configuration instance. */
-+ (instancetype)configuration;
++ (instancetype)configuration DEPRECATED_MSG_ATTRIBUTE("use +[RMConfiguration sharedInstance]");
 
 - (RMConfiguration *)initWithPath:(NSString *)path;
 

@@ -37,7 +37,7 @@ static RMConfiguration *RMConfigurationSharedInstance = nil;
                                                               cachePolicy:request.cachePolicy
                                                           timeoutInterval:request.timeoutInterval];
 
-    [newRequest setValue:[[RMConfiguration configuration] userAgent] forHTTPHeaderField:@"User-Agent"];
+    [newRequest setValue:[[RMConfiguration sharedInstance] userAgent] forHTTPHeaderField:@"User-Agent"];
 
     return [NSURLConnection sendSynchronousRequest:newRequest returningResponse:response error:error];
 }
@@ -52,7 +52,7 @@ static RMConfiguration *RMConfigurationSharedInstance = nil;
 {
     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:aURL];
 
-    [request setValue:[[RMConfiguration configuration] userAgent] forHTTPHeaderField:@"User-Agent"];
+    [request setValue:[[RMConfiguration sharedInstance] userAgent] forHTTPHeaderField:@"User-Agent"];
 
     return [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
 }
@@ -67,7 +67,7 @@ static RMConfiguration *RMConfigurationSharedInstance = nil;
 {
     NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
 
-    [request setValue:[[RMConfiguration configuration] userAgent] forHTTPHeaderField:@"User-Agent"];
+    [request setValue:[[RMConfiguration sharedInstance] userAgent] forHTTPHeaderField:@"User-Agent"];
 
     NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:error];
 
@@ -89,7 +89,7 @@ static RMConfiguration *RMConfigurationSharedInstance = nil;
 @synthesize userAgent=_userAgent;
 @synthesize accessToken=_accessToken;
 
-+ (instancetype)configuration
++ (instancetype)sharedInstance
 {
     static dispatch_once_t onceToken;
     dispatch_once(&onceToken, ^{
@@ -99,6 +99,11 @@ static RMConfiguration *RMConfigurationSharedInstance = nil;
     return RMConfigurationSharedInstance;
 }
 
++ (instancetype)configuration
+{
+    return [[self class] sharedInstance];
+}
+
 - (RMConfiguration *)initWithPath:(NSString *)path
 {
     if (!(self = [super init]))

@@ -184,8 +184,8 @@
 
 - (NSURL *)canonicalURLForMapID:(NSString *)mapID
 {
-    NSString *version     = ([[RMConfiguration configuration] accessToken] ? @"v4" : @"v3");
-    NSString *accessToken = ([[RMConfiguration configuration] accessToken] ? [@"&access_token=" stringByAppendingString:[[RMConfiguration configuration] accessToken]] : @"");
+    NSString *version     = ([[RMConfiguration sharedInstance] accessToken] ? @"v4" : @"v3");
+    NSString *accessToken = ([[RMConfiguration sharedInstance] accessToken] ? [@"&access_token=" stringByAppendingString:[[RMConfiguration sharedInstance] accessToken]] : @"");
 
     return [NSURL URLWithString:[NSString stringWithFormat:@"https://api.tiles.mapbox.com/%@/%@.json?secure%@", version, mapID, accessToken]];
 }
@@ -358,7 +358,7 @@
 
 + (BOOL)isUsingLargeTiles
 {
-    return ([[RMConfiguration configuration] accessToken] && [[UIScreen mainScreen] scale] > 1.0);
+    return ([[RMConfiguration sharedInstance] accessToken] && [[UIScreen mainScreen] scale] > 1.0);
 }
 
 - (NSString *)uniqueTilecacheKey

@@ -140,8 +140,8 @@
 
 - (id)initWithMapboxMarkerImage:(NSString *)symbolName tintColorHex:(NSString *)colorHex sizeString:(NSString *)sizeString
 {
-    NSString *version     = ([[RMConfiguration configuration] accessToken] ? @"v4" : @"v3");
-    NSString *accessToken = ([[RMConfiguration configuration] accessToken] ? [@"?access_token=" stringByAppendingString:[[RMConfiguration configuration] accessToken]] : @"");
+    NSString *version     = ([[RMConfiguration sharedInstance] accessToken] ? @"v4" : @"v3");
+    NSString *accessToken = ([[RMConfiguration sharedInstance] accessToken] ? [@"?access_token=" stringByAppendingString:[[RMConfiguration sharedInstance] accessToken]] : @"");
     BOOL useRetina        = ([[UIScreen mainScreen] scale] > 1.0);
 
     NSURL *imageURL = [NSURL URLWithString:[NSString stringWithFormat:@"https://api.tiles.mapbox.com/%@/marker/pin-%@%@%@%@.png%@",

@@ -78,7 +78,7 @@
     _activeTileSource = nil;
     _backgroundFetchQueue = nil;
 
-    id cacheCfg = [[RMConfiguration configuration] cacheConfiguration];
+    id cacheCfg = [[RMConfiguration sharedInstance] cacheConfiguration];
     if (!cacheCfg)
         cacheCfg = [NSArray arrayWithObjects:
                     [NSDictionary dictionaryWithObject: @"memory-cache" forKey: @"type"],