Moves CLI version suffix from preview1 to preview2
Sets channel for preview2 to 1.0.0-preview2, abandoning the Beta channel to the 1.0.0-preview1 release. Once @sokket's publishing cleanup work is complete we can re-converge the channels if desired.
Created a new command resolver called OutputPathCommandResolver which
reolves a command from the project build output directory.
Made changes ProjectDependenciesCommandFactory to use
OutputPathCommandResolver if the target framework is Desktop.
Fixes - #2126
Still need to add tests.
