New completers and code enhancements

Code enhancements

1.  Added verbose messages to Update-ArgumentCompleter. Sample output:

VERBOSE: Scanning for completer files...
VERBOSE: Registering completer 'Clean-MailboxDatabase
Get-MailboxDatabase Remove-MailboxDatabase'
VERBOSE: found initialization function, creating key: 'ex2010'
(...)

2. Added FilePath parameter to Update-ArgumentCompleter. Developing
completers can be a daunting task especially when you introduce rapid
changes to a completer file. Having to to load ALL completers in order
to load your changes can take very long time to complete and  slows down
development time. FilePath allows loading a specific file(s). On a side
note, a new completer file was added too to support file path completion
from the module base path.

New module completers

1. CimCmdlets
2. ISE

New custom completers

1. Import-Module Name Completer (core)
2. Get-WinEvent, ListLog and ListProvider completers (diagnostics)
3. WMI Namespace completer (similiar to buil-in cim cmdlets namespace
completion support)
4. Update-TypeData SerializationMethod completer (utility)
5. Register-EngineEvent SourceIdentifier completer (utility)
6. Update-ArgumentFilePathCompleter (TabExpansionPlusPlus.ps1)