* Multi-thread server lookup to increase perf for multiple subscriptions
* Use parallel execution for listsubscriptions
- Also refactored parallel execution code to be a bit more generic
* Initial credential service files
* Clean-up hostloader
* Update build scripts to build credentials archive
* Move hosting files to new assembly
* Add credentials files to MS.SqlTools.Credentials
* Remove duplicate files
* Update namespace in program.cs
* Fix test build breaks
* Update extensions visibility.
* Remove unused resource strings
* Add xproj files to SLN for appveyor builds
* Fix appveyor build break in test project
* Fix extensibility tests
* Fix various typos in latest iteration
* Add settings for Integration build
* Fix codecoverage.bat to use full pdb for new projects
* Fix bug when packing in folder with native images
* Fix typos in xproj
* Reset XLF to fix build.cmd