Added tests
Boot files from 09c4f91
Comment
Minor simplifications to FOR
Test EACH instead of FOR

FOR should be a compiler primitive that isn't used directly since it
doesn't provide proper scoping in JS. In the future, modules will make
this clearer.
Support "_" (ignored variable) directly in the reader
Make variable binding in FOR consistent between JS and Lua
Added test
Use flags for DEFINE-SPECIAL parameters
Minor renames
Additional cases for SPLIT