Nice to have pre-defined character classes

[lawrancej]

It'd be nice to have convenience functions to produce the following character classes. Don't create separate classes for these, just use the character class definition (or compilerkit_alternation) from issue #27. Each of these will probably be one-liner functions inside src/convenience.c.

/** Return a character class corresponding to [0-9] */
GObject *compilerkit_regex_digits(void);
/** Return a character class corresponding to [a-z] */
GObject *compilerkit_regex_lower(void);
/** Return a character class corresponding to [A-Z] */
GObject *compilerkit_regex_upper(void);
/** Return a character class corresponding to all punctuation */
GObject *compilerkit_regex_punct(void);
/** Return a character class corresponding to all whitespace */
GObject *compilerkit_regex_whitespace(void);

[theCompanyDream]

I can do this

[lawrancej]

I added in stubs for you.

[theCompanyDream]

issue complete