feat(classes):Implements Matching #'s & @'s On User Input'

NSString+AVTagAdditions Changes:
- endOfStringHashtagRegex -> endOfStringTagRegex
-- Regex Adjusted to match # or @ at the start
- endOfStringHashtag -> endOfStringTag
-- Returns an NSDictionary with keys of type and tag
-- type will be either '#' or '@'

UITextView+AVTagTextView Changes:
- Adds AVTagTextViewTagTypes enum for #, @, or all
- Updates performSearchForTextView: for new NSString implementations