Added advanced function: Get-VMToolsUpgradePolicy
Updated the following advanced functions to add functionatlity:
- Set-VMToolsUpgradePolicy - Supports UpgradeAtPowerCycle and Manual
- Update-VMToolsConfInVM - Supports all log levels now
Misc other minor updates:
- cmdlets changed to 'advanced function'
- 'vcetner' changed to 'vcenter'