Add -Location to Write-PSHTMLInclude

[Stephanevg]

In order to be able to filter on Location of the include file, the follwing things needs to be done:

1. Rename the Class Include to IncludeFile
2. Rename the Class IncludeFile, to Include
   // The inheritence of the includes has been set in the wrong direction.
3. Add a property called Location to the (Newly renamed) Include class. This propery can have the following values

• Module (Includes located in $Moduleroot\Includes\
• Script (Includes located in $Scriptroot\Includes\

4. Add a switch bound to a parameterSet in Write-PSHTMLinclude called Location. The dynamic parameters of the function should sort things out, and only display the includes from a particular location if one is specified in the -Location parameter.