Fixed formatting errors discovered by PAReview - extra blank lines and whitespace at the end of files.

Separated out functions that are not hooks that were previously in the module file into include files.

Combined two queries in deepsurvey_view and updated some instances of drupal_set_message where t() was not being used.

Removed ampersands from derefenced variables in function calls, and changed one call_user_func to call_user_func_array.

Removed default_value and not_null attributes from survey open and close date database fields as this was causeing the current date not to display in the appropriate fields when editing a survey in which these values had not been set.

Updated open and close date variable names to be survey rather than deepsurvey to shorten a long statement which wasn't very readable.

Fixed bug that was stopping survey_competed and survey_closed text from being edited and added check_markup for those when they are displayed.

Added the ability to change the message displayed at the end of the survey or if the survey is closed.

Fixed a bug with question verification where assign limits on the number of responses were not being enforced.

Updated deepsurvey.admin.inc due to new PAReview errors. This is to check what the requirements are before doing the rest of the modules.

Fixed a bug in the skip where the row code was evaluated using the operator when the column code should have been.

Fixed a bug in the way the next item to be displayed in the survey was determined which resulted in the survey ending prematurely.

Fixed problems that were occuring when node were being dleted but still referenced in tables owned by other content types. Each registered module will not be required to have a {module}_delete_content_type_node function which should be called from hook_delete by other nodes.
Each content type will thus handle it's own clean-up

Fixed issue with skip target drop down list options. They were incorrectly filtered based upon the response question selected, now changed to be filtered based upon the location of the skip.