Add type hints in SchemaShell.

I'm trying to figure out what's going on in the failing travis builds.
Expanding year range based on the provided value.

This solves issues where editing a record with a year outside the year range would leave the year selection empty, as now it will expand to accomodate the value.
Keep default=false for boolean columns
better with strict comparison
Merge pull request #1160 from remidewitte/feature/schema-update-default

Keep default=false for boolean columns
Remove appending to $errors on success/failure.

Logging boolean values offers no real value, and just balloons memory
consumption. While removing this may cause userland problems having it does as
well.

Fixes #3657
Properly initialize variable.

Fixes #3658
Update version number to 2.3.1
Merge branch 'master' of git://github.com/cakephp/cakephp
Update Plugin and Cakephp