Merge pull request #394 from am11/master

Code: Refactor and minor improvements
File icons: Update the .bundle icon
Markdown: Enabled custom CSS button. Fixed #396
Root folder cleanup
Tests: Fix spelling errors
Tests: Fix FluentAssertion extension messages

Make messages consistent with
FluentAssertions built-in messages
Tests: Clean up VSTest class

Rename to VSHost
Use property instead of method
Tests: Reorganize test folders

Fix casing, remove unnecessary folders
Merge pull request #397 from SLaks/test-cleanup

Cleanup unit tests
Merge pull request #398 from am11/master

Misc fixes