Added support for urdu and its local variants

- (NSString *)localizedStringForKey:(NSString *)key
withDefault:(NSString *)defaultString
Gives preference to the user locale setting thus if a local identifier
string is found within the iRate.bundle it is used.
For the time being
ur.lproj
ur_IN.lproj
ur_PK.lproj
contain the same localized strings.
Merge pull request #101 from HHuckebein/master

urdu support/localizedStringForKey:withDefault prefers locale setting