Added UninstallSolution method, rewrote InstallSolution, added tests

* Rewrote InstallSolution method to upload solution method to rootfolder and activate it from there, instead of uploading it to the solution gallery. Previously 2 wsp files would show up, solution.wsp and solution.wsp.v-1.0.wsp which could cause confusion. Now only one activated solution shows up. The file is removed from the rootfolder after activating the solution.
* Added uninstallsolution to remove an existing solutions.
* Added tests for both methods.