Use the real name for a LuaReference
Support QStringList serialization
Upgraded ax_have_qt macro
Remove what appears to be a typo
Support all QVariant usertypes, not just the predefined list
Support QHash insertion and retrieval for QVariants
Add support for LuaProxy, for heterogeneous LuaValues

LuaProxy lets methods accept any type of LuaValue<T>, rather than forcing
clients to name a particular type.

This honestly feels more of a workaround behind the fact that LuaValues
are templated on their accessible type. It seems much more natural to
just have LuaValue always use pointers. However, I'm not sure how the
performance would suffer, so I guess I'll keep LuaProxy around until I can
be sure the benefit of performance is insignificant.
Bump version to 2.1