(Correction) Changed to using REST API

- As per discussion here:
	https://github.com/Particular/GitVersion/pull/262
- Changed to use the AppVeyor REST API SetVariable method, instead of setting an Environment Variable
bump version
fix last minor version finding
Merge pull request #273 from gep13/AppVeyorCorrection

(Correction) AppVeyor - Changed to using REST API when calling GenerateSetParameterMessage
fix inspection
add test for #253
fix support naming with slash

fixes #197
fix Incorrect Semantic version written from task

fixes #274
bump version