Fixed version and download path
Bump up system requirements

Makes the readline/libedit hack obsolete too
Updated most packages to newest versions available

I left out the Atmel toolchain for now. Also avrdude 6.1 didn't compile cleanly so I left it out for now.
Update to latest Atmel toolchain

gdb is now part of the Atmel toolchain. Headers now seem to have been fixed so the patches are no longer necessary.
Removed hack for older versions of OS X