The javascript code is almost compliant with JSLINT

In addition all exceptions are logged to the web2py ticket system.
Fix a bug in App.form.Panel.onStoreException and improve it.

possibility to modify the ExtJS configuration parameter of the
underlying combobox.

of the master store

resetgrid event.

initialWhere attribute of the store. Use the method store.restoreWhere
as well.

resetgrid.

the GridFilter. Remove the obsolete pGridExport.

The title of the selector can be defined in the python code.
The selector position can be top/bottom/left or right.

Add the method repr_url in Selector.
rename the module report.py as selector.py

without loosing what have been done at the previous step.