Start getting the regex compiler in place.

Implemented concat, literal and pass. Empty, cheating scan so we can
try the other bits. Also got most of the prologue being emitted, but
none of the postlude that handles backtracking yet.
Implement nqp::findmethod.
Uncomment parse, wich ACCEPTS calls to match.

With this, it's now possible to do a very, very basic regex:
    use QRegexJVM; say(('abcdef' ~~ /abc/).Str())
Which produces 'abc' as output.