* New and complete character class support
* string.gsub implemented
* rawset implemented
* lua_call added (based on lua_pcall)
* lua_pop added
* newCall removed; luaGetTable and luaSetTable in LFunction updated to
use lua_call instead.
* StandardTest changed to avoid an ArrayIndexOutOfBoundsException
Unfortunately I discovered a problem where execute() will loop around too
many times and call exec() with a call frame that has already completed.
This might be due to the lack of the "tailcalls" field in our CallInfo class
that the C version maintains?
factor out negative index handling to separate function, posrelat (to
match C Lua). When converting numbers to strings, see if the double value
can be represented exactly as a long, and if so format the string as
an integer. With these changes the standard test case "strings.lua" runs
to line 104 (over half way through!), where it uses string.format.
(1) Fix string.char and string.byte (argument indexing was off by one)
(2) Implement string.find
(3) Change calls to charAt, which does array bounds checking, in the
pattern matcher with calls to luaByte, which does not.
(4) Replace use of recursion with while/continue in pattern matcher.
