Remove validates_timeliness

This library has been abandoned, has been producing deprecation warnings and is only used to validate a single field so remove it and perform the validation ourselves.

This is of arguable value but the deprecation warnings were annoying me. Also, the validator is only tested by the model specs.

Any opinions?
In above if statement you see if the value is nil and in this line you see if the value is different from the original value. Are you sure that this line will be executed? And what particular scenario this line will be executed? Can you add tests for this validation containing all scenarios?