Fixes massive rust fallout based on https://github.com/hackndev/zinc/pull/94

 * to_str() is now to_string()
 * typaram doesn't have size specification any more
 * LIT_INT_UNSUFFIXED is now LIT_INTEGER and a bitch to parse
 * minor changes to CustomEmitter trait
Fix travis build for new non-rpath world
Merge pull request #95 from farcaller/fix-rust

Fixes massive rust fallout

Reviewed-by: farcaller