Added failing test to prove #4019
Fixes #4019
Merge pull request #4024 from cakephp/3.0-save-deep-btm

Fixes #4009
Merge pull request #4025 from cakephp/3.0-entity-context-fix

3.0 entity context fix
Merge pull request #4012 from cakephp/issue-3997

Fix a bunch of small issues.
Add `.` to the list of allowed characters.

This was missed when the email validation rules were relaxed in
dc34d80f6f622e883b8c7db9ef489bd514c8701f.

Fixes #4027
Remove x flag on FormHelper.

No need for it to be there.
Remove CacheHelper and related features.

CacheHelper is going to be split into a stanalone plugin for 3.x.
Removing this code will reduce confusion in the future about how to do
caching.
Fix build failures.

The recent Query->join() changes contained an invalid column name, and
the changes to EntityContext necessitated changes in the tests to
reflect what should have always been reality.
Add note about identifier quoting in pdo error template.

Hopefully that should avoid a few unnecessary tickets.
Merge pull request #4030 from ADmad/3.0-pdo-error-msg

Add note about identifier quoting in pdo error template.
Merge pull request #4029 from cakephp/build-fix

Fix build failures.
Removed dead test file
Added a .mo file loader
Starting to rename some file
Moving the parser files ot a better location
Abstracting the old MessageLoader so that it can use any parser
Cleaning up some code
Remove dead code in test stub.

This code does not work and will trigger notice errors if it was
actually run.
Added a chain messages loader to automatically load .mo files if available