Updated test suite to rspec 3.0.
Incremented version number to 2.0 for NLRC.exe v2.1.

The new version of the NetLinx Compiler (bundled with NetLinx Studio 4) breaks
compatibility with netlinx-compile 1.x.
Added Duet workspace that causes NLRC.exe v2.1 to hang when both an include
file and Duet module are used in a project.