Option to skip full analysis

OK, I lied about no more features in 1.1 - I need this for a project I'm working on. Doing the full data analysis on large tables (the MIN/MAX queries in tw_perform_analysis()) can take a long time. When programmatically adding large tables in install/update hooks, timeouts can occur. So, I will add a flag parameter to tw_add_tables and tw_perform_analysis to allow skipping the hairy queries (holy cow!). I'll also add a toggle to the Add Existing Tables fieldset for quick adds.