Rough implementation of showing when last updated

Need to make a custom dialog in order to visualise the time nicely.
Added onPrepareDialog to modify last updated text

/src/org/osuosl/ocw/Schedule.java
Added string for last updated dialog

/res/values/strings.xml
Added custom view for last updated dialog
refresh progress dialog text changes depending on what is being loaded
Removed loading text from splash screen
renames time id to timeSlot to distinguishe from listEvent id with same name
Reuse view rather than inflating a new one when available
Check if reusing a listevent that had a track when event doesn't have one.

/src/org/osuosl/ocw/Schedule.java: Because some events don't have tracks, i.e. "registration", we must check if the view being reused was from an event that does have a track and if so remove the track text.