Support the rest of QLike ops, incuding all regular expression functions

[xsawyerx]

This supports the following:

• m// - Similar to QLike functions but with modifiers (like qr//)

• s/// - Similar to m// but has two arguments and modifiers

• tr/// - Similar to s///

• y/// - Similar to y///

• qr{}'s regex modifiers

• // - Similar to m// but without even a function name

• ` - Similar to qx// but without even a function name

• We separated what has modifiers, what doesn't.

• We don't allow subroutines that can be called q/qq/qw/qx/qr/m/s/tr/y.

• We also support delimiters that appear double (s{}{}).

However, because of how I implemented this, we don't support stuff like:

s {foo}   # Replace foo
  {bar};  # with bar.

If we want to support this, we'll need to do this across all QLike operators: s///, y///, tr///, m//, qw//, etc.

I don't think we should support that, to be honest, despite the convenience of putting regexes there.

[xsawyerx]

@vickenty I realized phase statements in sub definition (sub BEGIN {...}, etc.) were broken (identified as both a PhaseStatement and a SubStatement) and had to be supported in the same crazy hack.

Please review this horrible commit: https://github.com/xsawyerx/reimagined-guacamole/pull/39/commits/65633b222e07500ff5ffa4cff01c371b16616922.

Alternatively, we can avoid identifying sub BEGIN {...} as a PhaseStatement, but then people would get different results between BEGIN {...} and sub BEGIN {...}.