Tidy and constants
Add Windows Error Codes to Windows Post Mixin
Remove errant fullstops
Docs
Move to module
Filename match module
Remove ERROR_

To access as Error::NO_ACCESS
Organise service constants

Try to establish some sanity to file...
Use railgun string constants

Remove unnecessary constants
Bit of tidying
Merge branch 'windows_error_constants' into extapi_service_post

Conflicts:
	lib/msf/core/post/windows.rb
Use Error mixin