Add "personalize" button in personalized view

[MrTitainin]

Current behaviour:
Personalization button (the one that leads to URL with /personalize/) is visible only in "class" view (URL with /class/), not in "personalized" view (URL with /groups/).

Desirable behaviour:
Personalization button is also visible in "personalized" view.
Preferably it should retain choices that user made to get such view (i.e. if personalized view includes groups 144 and 938, their corresponding checkboxes would be checked automatically).
If class that should be selected is ambigious, appropriate error with option to return to main site should appear.

Explanation:
It would be easier to correct groups. Especially useful for 1st grade students that don't know their groups in advance.

[DietPawel]

Firstly, sorry for misclick.

Secondly this feature seems easy to add, however it’s not very needed.

If you commit an error during groups selection just use back feature of web browser and fix errors.

Also no point to personalize your timetable unless you know your groups.