Rainbows! 4.6.0 - fix unicorn 4.8.0 compatibility
The unicorn 4.8.0 internal changes unfortunately broke some
unoffically supported behavior we depended on. This release fixes
that, but as a result, we lose compatibility of older unicorn
versions. (Oops!, oh well... :x)
There's also minor bugfixes and documentation updates.
In order to ease transitions to future versions of the GPL, we are
now "GPLv2 or later" instead of explicitly GPLv2 + GPLv3(-only).
The old Ruby 1.8 license remains an option. If the FSF turns out
a horrible GPLv4, users are free to continue using GPLv2 or GPLv3.