feat #430 revert of the feature

This commit reverts commits 5a0b9dd7fdbf86cff3b96d0040192416b4923029
and 46e0e12e12f9154802f1ffbfd175e24e0b786506 as they are causing
regressions: test test.aria.ext.filesgenerator.GeneratorTest is failing
when not in debug mode.
fix #450 Number controller didn't reference the right configuration error message.

aria.widgets.Widget.INVALID_CONFIGURATION has been moved to aria.core.JsonValidator.INVALID_CONFIGURATION,
after commit b129e79