Adding some powershell niceties and fixes for spaces in the folder path.

I've added quotes (and &quot; in xml) that should help prevent breakage when trying to run Cmder.bat from another folder and/or if the cmder folder has a parent folder with spaces in the name.

Added several arguments to the powershell launch command, which solidifies the launch options for portability, not loading the default powershell profile from My Documents, etc.

Added a scripts/powershell folder with a DefaultProfile script so you can have a portable profile self contained in Cmder. Anything added to this script will execute on the default powershell run in Cmder with the change to config/ConEmu.xml.

Added a convenience "dropbox" for scripts called autorun, the first of which is a prompt redefinition to make the powershell prompt look exactly like the cmd.exe one. Also a good base for people to customize.