Allow to execute pcall(error(T)) when T is a table
Add error wrapper for values from error()
Call error object metamethod, if object has one

Lua 5.2 docs
"if the error object has a metamethod __tostring, the interpreter calls this metamethod to produce the final message"
Merge pull request #36 from loucash/develop

Allow to execute pcall(error(T)) when T is a table