#412 remove active groups settings from mod_form to avoid inconsistency
#437 remove sorting functionality for userlist's registration and queue columns
#428 clean param manual for from/to/digits fields

To avoid problems with non-digit-characters in these fields we cleaned the params by hand so we can catch some nonvalid input data.
#427 clean param manual for amount field

To avoid problems with non-digit-characters in these fields we cleaned the params by hand so we can catch some nonvalid input data.
#415 clean param manual for group members

To avoid problems with non-digit-characters in these fields we cleaned the params by hand so we can catch some nonvalid input data.
#408 workaround for permission-problems when creating events
#425 prevent errors after conflicts in groupnames have been detected
#439 fix conditions for showing myMoodle-output
edit just for push
#661 fix typo in english language file
#420 enhance module description

Due to some missunderstandings concerning differences between Moodle-Groups and their Grouptool-representations, the modulename-helpstring has been extended with an alerting paragraph.
#439 display general grouptool overview even if registration is disabled

On the MyMoodle-page every grouptool will display it's name, available-from and due-dates (if the user has either capability to register or work with the grouptool). If selfregistration is enabled, additional information about the registrationsstatus will be displayed.
#436 add option to force registration for imports

In addition some minor bugs got fixed preventing wrong variable access and possible leak of usernames + userids of bigger selections of users in import message.
replace double quoted string with single quoted one
fix message displayed instead of userlist if no users present