Merge pull request #31 from quarklang/codegen

Codegen
Merge pull request #32 from quarklang/codegen

Codegen
Merge pull request #33 from quarklang/codegen

Codegen
Add relational operator (<, >=) support for string, fraction, and fraction-int/float
Add grammatical rules for python-style tertiary
Fix tertiary grammar. Lower IFX and ELSE precedence
Add semantic check and codegen for Tertiary