Update jQuery UI

jQuery UI was updated from 1.9.2 to 1.10.3
The installed version is a custom jQuery UI which includes the functionality
that was already present in the custom 1.9.2 (core, widget, mouse, draggable,
selectable, resizable and sortable) plus datepicker.

The old css file will not be updated but a css for datepicker has been added.
Use jqueryui for asset reservaton
Display only times in which there are available slots

ReservationCount resource has been created, this resource can only be accessed
by requesting a list indicating the desired day and the id of the asset the
information is being requested. The resource will contain information about the
number of reservations which exist in each suitable time.

Classroom view was modified so only time when there are available slots are
available for selection in the combo box.
Denote the occupation of each day in the booking dialog

In the date selection calendar of the booking dialog, the color of the
background of each day will depend on the occupation of that day.

OccupationInformation resource will provide the needed information.

Created helper function get_occupation_for_month which will query the cache and
the database for obtaining the information.
Solve style issues
Disable "Confirm" button in reservation dialog if there are no available times

If a date is not selected, or the selected date do not have any available slots
available, it will not be possible to click the "Confirm button".
Handle jQuery UI languages
Make date parameter compulsory for ReservationCount

If a date is not specified or the format is incorrect, an empty list will be
returned.
Take into account result from cache
Merge branch 'master' into feature-assets-newcalendar
Solve issue when deciding if a time should be shown
Merge branch 'master' into feature-assets-newcalendar
Merge pull request #43 from OpenMOOC/feature-assets-newcalendar

Feature assets newcalendar merged into master