Deprecated tableize()

I vote for deprecating this method in 3.0 beta and remove it in 3.0 stable.
Since the main usage in 2.x was from Singular ModelName to plural table_name, this was fine.
But now in 3.x the table classes are in plural and therefore this method does not really make much sense anymore and would/should simply be a wrapper for underscore().

We should rather use underscore() directly to go from table class (plural) to table name (also plural).