New Microsoft.PowerShell.Core completers

Added two new completers:

1. Completes the -Module argument to Save/Update-Help cmdlets
2. Completes the -Scope argument to the *-Variable, *-Alias, *-PSDrive
functionality to Disable/Enable completion

Added functions to control completion functionality
Get-ArgumentCompleter enhancements

1. Added Name parameter to enable filtering by command name

PS> Get-ArgumentCompleter get*

2. Added File property to ArgumentCompleter objects so you can quickly
tell which file it a completer was loaded from:

PS> Get-ArgumentCompleter out-* | fl file

File : Microsoft.PowerShell.Utility.ArgumentCompleters.ps1
Remove unnecessary =$true attribute arguments.
Use Get-CommandWithParameter instead of Get-Command
Added File property to ArgumentCompleter objects

I removed the Enable/Disable-TabExpansion functions, replaced tabs with
4 spaces per TAB character and added the File property to include the
File name that contains the completer.  I left the Name parameter I've
added to the Get-ArgumentCompleter function in place.
Fixed tooltip

I have fixed the tooltip but (for visual formatting purposes) kept it on
one line inline instead of using a here-string
Merge branch 'master' of https://github.com/ShayLevy/TabExpansionPlusPlus into ShayLevy-master
Fix formatting, use string[], incorporate feedback