Wrap Ruby array functions (wikitext, 7566594)

This is the first step towards replacing the Ruby array calls with pure C ones which will hopefully be much faster. Profiling indicates that a large part of the parse time is spend inside rb_ary_includes (as much as 28%, even more than the time spend in the next_token function, which only occupies 14%), so I’m hoping to see decent speed boosts from this.

Signed-off-by: Greg Hurrell <greg@hurrell.net>