Addresses issue #37:
- in redcap/driver.py: raise the exception to read the redcap error message
- in Base.py: processResponse was changed to read the message from Redcap's API
- in formBuilder.py: display error message through javascript
- in formBuilder.py: create validation map and method fieldValidation
- in formBuilder.py: Y->y so that isRequired message displays on table
- changed test_process_form_badresponse unit test so that it asserts a different message