Define CLOCK
Remove unused export
Remove the SD function from runtime
Don't sort generated code
Roll back support for identifiers that start with a numeric character
Minor simplification, rename
Remove an unnecessary check in VALID-ID?

The call to SPECIAL? was really just a stop-gap until we introduced
RESERVED?.
Remove CLOCK
Minor whitespace
Minor refactoring of REIMPORTED
Remove FLAT/FLAT1
Remove SPLICE in order to simplify MAP
Minor rename
Moved code from runtime to lib
Minor whitespace
Extract math functions into a separate module; moved code
Unify the JS and Lua implementations of JOIN
Unify SPLIT for JS and Lua