PATCH: Limit 100 default in frmEditGrid.cpp

I propose a small patch to frmEditGrid.cpp that changes the default limit form "No limit" to "100 rows".

Another option, more coherent in design to the rest of the program, can be disabling automatic run and let the user configure the option before. I think there are a small number of forms that are performing long operation at the show time without the explicit user action.

Cheers,

Matteo Bertini