Fix some LuaJ bugs (Not tested for LuaJ 3)

LuaDouble:
Do not try Long.toString
Do not cast to float

LuaString:
Do not scan as a long
Add another check in scandouble (was scanlong)
Have substring create new bytes to work with
Forgot an import

import java.util.Arrays
Adds support for the environment variable _

http://istasi.dk/printenv.png yes, this clearly editted, due to my heighten paranoid level
Merge https://github.com/gamax92/OpenComputers
Merge branch 'patch-2' of https://github.com/istasi/OpenComputers
Avoid potential assertion error.