Version bump to 0.28.6.pre
Use of Ruby 2.1.2 is now recommended
Updated to rails 4.1.1 and other gem updates

**Gem Changes**
  - Updated to rails 4.1.1
  - Updated to contour 2.5.0
  - Removed turn, and replaced with minitest and minitest-reporters
  - Removed Windows-specific gems
Updated to redcarpet 3.1.2
Updated email styling template
Version 0.28.6 finalized