cljs.reader parses radix form of int literals (e.g. 2r101) incorrectly

fixed https://github.com/clojure/clojurescript/commit/56ea020fd9b15df220ba247f73b68873f041d8ef

Rebased patch.

Can we get a new patch rebased on master? Thanks!

Turns out other integer literals were broken besides radix due to a re-match problem (CLJS-776). Patch includes fix and tests for all the different integer literal forms.

Floats, ratios, and symbols/keywords might also have parsed incorrectly in certain cases, but I did not produce failing tests to confirm.