Merge pull request #102 from k06a/extnil-impovement

Implemented self method on EXTNil

Author: jspahrsummers

extobjc/EXTNil.m

@@ -28,6 +28,10 @@ - (id)init {
     return self;
 }
 
+- (instancetype)self {
+    return nil;
+}
+
 #pragma mark NSCopying
 
 - (id)copyWithZone:(NSZone *)zone {