core: improve guest type detection

/cc @fgrehm - I figured you might be interested in this. :)
add ONBOOT and NM_CONTROLLED to redhat/network_static

Fixes private networking on Centos 6. It seems using Network Manager (NM_CONTROLLED) to change an interface while running is a bad idea. I'm not sure of any specifics though. This is the only way I could get it to work.
Merge pull request #2605 from teaforthecat/patch-1

guests/redhat: add ONBOOT and NM_CONTROLLED to redhat/network_static
v1.4.0
up version for dev
scripts: calculate shasum
website/www: bintray downloads
website/www: link to book on support page
website/www: its time the homepage used precise32
website/www: properly center button
website/www: 1.4 release announcement for tomorrow
website/www: link to downloads