updated switchToWindow tests according to updated BrowserTest class
added find by AttributeIs and some minor refactoring changes in tests
added missing test file
Merge pull request #22 from adeel41/AttributeIsElementsFinder

fixed #14 by adding AttributeIs method in XenonElementsFinder and some minor refactorings in Tests Project
Merge pull request #8 from LiquidThinking/master

pull changes from origin