Require ActiveSupport

core_ext depends on ActiveSupport::Autoload, which may be missing, especially on non-Rails stack.
Add --color to .rspec
Remove color option from spec_helper
Rspec 3 syntax + require rspec >=3
Merge pull request #2 from jnv/master

Require ActiveSupport
BUMP 0.1.5
Merge branch 'release/0.1.5'
Merge tag '0.1.5' into develop

Release 0.1.5