Remove doc symlink

This snuck in with #167
Merge pull request #169 from bjz/remove-symlink

Remove doc symlink
Build external tests using cargo
Merge pull request #170 from bjz/macro-tests

Build external tests using cargo
Severe cleanup of the shader param constructor on the renderer side
Another redesign of how shader parameters are generated and assigned.
Re-implemented  for the new interface
Refactored  into a struct to simplify macros code and avoid warnings. Moved parameter extraction into
Cleaned up shade namespace export. Improved program shell error checking and reporting.
Implemented ParamDictionary
Disabled fake handles for non-test configurations. Switched  to store s for mode idiomatic code.