Starting from version 20160228 all scripting is moved to plugins and the documentation is in need of update check back later.
Starting version 20160221-221915 scripting engine moved from interpreter Lua 5.1 to compiler LuaJIT 2.0. Syntax of coding was not changed and now has several extensions. Please read about LuaJIT extensions here - http://luajit.org/extensions.html
Execution under LuaJIT can be checked using following method:
if jit ~= nil then -- Code is executing under LuaJIT end