queXS 1.15.0

New feature: Weighted timeslots (allow more attempts in particular timeslots)
New feature: Allow for tokens to be imported in a queXS sample

Fixed issue: Database structure not optimised for sample_var_import_restrict table
Fixed issue: Cases being generated without a valid email address when importing to Limesurvey
Fixed issue: Limesurvey save form not displaying
Fixed issue: Limesurvey welcome screen not displaying
Fixed issue: Admin permissions not propogating to Limesurvey
Fixed issue: Mode of delivery (single page, group by group, etc) not determined if no token in queXS

Database changes required:

INSERT INTO `sample_var_type` (`type`, `description`, `table`) VALUES(9, 'Token', '');
ALTER TABLE `sample_import_var_restrict` ADD INDEX ( `var` ) ;
ALTER TABLE `sample_import_var_restrict` ADD INDEX ( `sample_import_id` ) ;
ALTER TABLE `questionnaire_timeslot` ADD `weight` INT( 11 ) NOT NULL DEFAULT '1';
ALTER TABLE `questionnaire_sample_timeslot` ADD `weight` INT( 11 ) NOT NULL DEFAULT '1';