* Added tests for the engine classes.
* Added some tests that run under Lua.
* In the chunk names, fixed truncation of module names at 60 bytes
by using an "=" prefix instead of @.
* Fixed a bug in mw.clone() which was causing the metatable to be set on
the source table instead of the destination.
* Put restricted setfenv/getfenv in the cloned environment rather than
the base environment, they work better that way.
* In setfenv(), check for getfenv() == nil, since that's what our own
restricted getfenv returns.
* Fixed getfenv() handling of numeric arguments: add one where
appropriate.
Change-Id: I2b356fd65a3fcb348c4e99a3a4267408fb995739
