Code cleanup and report resources

A LOT of changes in this commit...
- Reorganised vCheck.ps1 - you will now see all functions grouped together, as well as sections for Initialization, Script Logic and Output. Makes it a bit easier to track down what is happening where.
- Added two new functions:
   * Add-ReportResource - used to add a resource that will be used in the report (i.e. Images)
   * Get-ReportResource - used in the report generation to return the specified resource in the format required
   Both of these are unfinished and only support embedded images from a file (like how the header is currently done). This functionality allows us to have rich reports- don't like boring "Enabled/Disabled" text? Include an image!
   VMware style now shows off this functionality by splitting the header into two files- each image aligned to a different side of the header.
- Updated all default styles to use *-ReportResource
- Bug fix for Get-HTMLList when no items are passed - was reporting error.
- Removed header plugin as it is no longer required
- Renamed disconnect plugin to 999 - now that we have over 100 it wasn't running last by default