Closes #198 #244 - Improve how 'fluo init' handles existing Fluo instance

...and make initialization easier for users

Pull request for #198 & #244 
it possible that table could be created here by another thread.  I think a simple way to avoid problem is to call exists() once and store the output.  Thay way all decisions are based on what it knew about existance at the beginnng and it will not delete the table.   Alternatively could recheck opts.getClearTable()