add better handling for `readonly` to prevent bugs from `const`-ifying the return value of a member variable (e.g., unexpected copy semantics)
add more tests and add a few more handlers for new readonly type
fix simple_usertype_metatable's handling of newindex and index when not at the top level
From the Catch docs:
Please note that the THROW family of assertions expects to be passed a single
expression, not a statement or series of statements. If you want to check a
more complicated sequence of operations, you can use a C++11 lambda function.
https://github.com/philsquared/Catch/blob/master/docs/assertions.md
In current versions of Catch violating this causes a build error.
Slight breaking change, but at the source level almost nothing changes (ipairs is the only thing that changes because for some reason it checks if what is passed is a table and that really doesn't make any fucking sense)
Closes#195Closes#196
