Add correct default date for clinic

This makes the default date to be the next available clinic date. Also
changed the next and previous buttons to jump between the weeks instead
of day to day
Change the layout of the date selection

Moved the date picker into a hidden link, can be activated by clicking
the link. Tidied up the prev next stuff
Force recompute loggedinUser on login
Merge pull request #90 from TheProductWorks/features/date-selection-updates

Features/date selection updates