AlarmingArmies

A few fixes, a few changes! Thanks to @cryptorick and @brycied00d for the AFTER feature!

Changelog:

• Allow EXTRACT_ONLY to be specified in ~/.snaprc
• Notify user we are using sysmerge (with -i)
• Use BUILDINFO when available
• Warn user when mirror has the same version as is currently installed
• Fix setting VER in ~/.snaprc
• Add ability to specify an AFTER script in ~/.snaprc, this will be copied to /etc/rc.firsttime
• Fix armv7 snapping