*Add the ability to stop the render thread
*Add the ability to stop the ngen thread
*Add the ability to detect the window close event
*Add gl_context_destroy function
*Close any open controllers
*Allows the nvmem to save

pi2 should now exit cleanly
pi2 should now save settings
general formatting clean-up

Note: Raspberry pi requires keyboard.cfg in /mappings
      to bind esc key

This is required for Launchers that make extensive use of the "-config" command
line option. Without it the RTC always resets to default because it parses a
virtual config instead of the emu.cfg file.

RetroPie is one of the main usage cases for this mode. If any RetroPie devs try these changes, be sure to open the Makefile and enable NO_VIRTUAL_CONFIG at
the top of the file.

I have rearanged the cfgopen() and parsecommandline() functions to accomodate this.

Add minor fixes for tab/space corrections.
Add minor fix for missing guards around closing evdev controllers.