Add requires for pptp_tunnel
Land #2032, @egypt's requires for pptp_tunnel
Add Msf::Post::Windows::Process

The purpose of Msf::Post::Windows::Process is have all the common
functions you might need to do something to a process, for example:
injecting something to a process and then run it.
Update documentation

Fix broken English
Fix a handle leak & change thread creation flag
Yarrrrrrrrd
Extra comments, no thanks
Land 2033, post lib for injecting shellcode