Tidy up fh_extract_string to be faster and cleaner, also a bit safer.
Combine single and double quoted strings since their actions are identical
Use POSIX character classes for more thorough matching
Performance improvements for regular expressions
Fix unmatched float issue when leading or trailing digits are ommited
Performance improvements to regular expression that matches RegExp
Tidy up indetation
Swapping calloc in place of malloc + memset
Swapping strdup in place of malloc + strcpy