Update branch regex to handle new standard naming scheme

MSP-9653

Branch format is now <type>/<story-id>/<summary>.
Move load_concerns to named initializer

MSP-9653

Extract load_concerns from config/initializers as downstream engines and
applications can't reliably schedule before or after concerns are loaded
when the initializer is unnamed.
Document named initializer usage

MSP-9653
Update PRERELEASE for branch

MSP-9653
Fix rbx install issue on travis-ci

MSP-9653
RSpec 3.0.0 compatibility

MSP-9653
Remove deprecated `require 'rspec/autorun'`

MSP-9653

RSpec 3 compatibility.
Rename spec for load_concerns initializer

MSP-9653

Have its spec file match its location in source.
Merge branch 'feature/MSP-9653/use-metasploit-concern-in-pro'
removing the prerelease tag from version.rb