Test for Byte Order Mark (BOM) on module files

[johlju]

Module files (.psm1) should be UTF-8, and not UTF-8 with BOM.
https://github.com/PowerShell/DscResources/blob/master/StyleGuidelines.md#correct-file-encoding

I have at least one resource that has BOM in it's module file, in xSQLServer.

Should we do a check for BOM for this files as well, like we do with markdown files?
Any other file types?

[PlagueHO]

This gets my vote.

[johlju]

Working on this now.