RegexKitLite 5.0 Migration

This first release includes an almost pure clone of the the RegexKitLite 4.0 ("RKL4") Objective-C API from John Engelhart. This version includes:

• Exposing NSMatchingOptions on the most argument-rich API call (not required to be used)
• Use of NSNotFound as the error return code if an API returning NSUInteger doesn't match the regex
• Use of proper NSArray collections for the block-based methods
• All code is ARC-compliant
• The Objective-C API is 100% Analyzer Approved!!
• Cursory tests demonstrating how to use each of the APIs
• Deprecated RKLRegexEnumerationOptions
• Deprecated all the RKLICURegex...Error keys

NOTE: If you use any of the block-based methods from RKL4, you'll need to update your code at the block signature level. Specifically, you'll need to convert the RKL4 API blocks from this kind of block signature:

- (BOOL)enumerateStringsMatchedByRegex:(NSString *)regex 
                            usingBlock:(void (^)(NSInteger captureCount, NSString * const capturedStrings[captureCount], const NSRange capturedRanges[captureCount], volatile BOOL * const stop))block;

to this kind of block signature:

- (BOOL)enumerateStringsMatchedByRegex:(NSString *)pattern 
                            usingBlock:(void (^)(NSArray<NSString *> *capturedStrings, NSArray<NSValue *> *capturedRanges, BOOL *stop))block;

It's a small conversion to NSUInteger and NSArray for the captureCount and capturedStrings block arguments.