Return *const T from Blob::get_address
Merge pull request #328 from bjz/blob

Return *const T from Blob::get_address
Move blob handling traits to a submodule.
Derive PartialEq for Handle
Remove import casts

This should make the code simpler to follow
Don't import std::mem::size_of directly

This is more in keeping with 'rust style'
Merge pull request #329 from bjz/module-structure-and-import-cleanups

Module structure and import cleanups
Implemented MSAA texture and surface creation/binding
Implemented Multisampling rasterizer state
Redesigned the MSAA flags on textures and surfaces, storing it as a part of Kind now.
Fixed device texture warnings.