Fixing memory leak

(CGColorRef) CGColor { CGFloat components[4] = {(CGFloat)_r, (CGFloat)_g, (CGFloat)_b, (CGFloat)_a}; return CGColorCreate(CGColorSpaceCreateDeviceRGB(), components); }
CGColorSpaceCreateDeviceRGB() returns a Core Foundation object with +1 retain count and this object is not referenced later and has a retain count of +1.
Merge pull request #691 from iSevenDays/patch-1

 Fixing memory leak