Merge pull request #463 from hojs/duplicated-test

Remove duplicated test
adding command line task completion for powershell
Merge pull request #467 from staxmanade/master

Adding command line task completion for PowerShell
PowerShell completion caching strategy

Adding a basic strategy which improves the performance of powershell completion.
Merge pull request #469 from staxmanade/master

PowerShell completion caching strategy
fixed typo in testing.md
Merge pull request #471 from mcharytoniuk/patch-1

typo in testing.md
Update powershell completion instructions.
correct regression
Merge pull request #473 from staxmanade/patch-1

Update powershell completion instructions.
Implement --tasks-simple