closes #3303 RFC: Rename Validator::between() into Validator::length()
replaces validator 'between' with 'lengthBetween'
fixes falling test case for 'lengthBetween' validator
adds backwards compatible 'between' alias for 'lengthBetween' validation rule
fixes model task test-cases for 'between' validation rule alias
Update version number to 2.5.1
Harden the `bin/cake` script to avoid breakage when local shell environment has a `CDPATH` set.
Add 'feedback' to uninflected single and plurals
Merge pull request #3530 from beporter/feature/bin-cake-cdpath-fix

Harden the `cake` script to avoid `CDPATH` breakage.
Merge pull request #3528 from Marlinc/patch-1

Add 'feedback' to uninflected single and plurals
Themes are now plugins, this unifies the intallation experience and
loading syntax
Starting to re-do theme assets handling
Relocating theme assets and updating tests
Fixing HtmlHelper tests
Fixing Helper tests
Fixing tests in dispatcher filters related to Themes
Fixing remaining tests related to themes
And... done fixing the tests
Fixing CS errors
Small style corrections