fixed some time checking
Merge pull request #4 from VWJF/MakeABookingServlet

Make a booking servlet
don't have to resubmit to change time desired
Added MakeBookingServlet.java error checking for a User that is not
logged in.
Reverted to the use of [start_date, end_date] [inclusive, inclusive].
Added reservation_time property to Booking entities. Records the time
the reservation was made (helps with debugging).
Cleaned up code.
Date Lie Outside Range Query for Inclusive End Dates [1].

[1]http://salman-w.blogspot.ca/2012/06/sql-query-overlapping-date-ranges.html
[2]http://c2.com/cgi/wiki?TestIfDateRangesOverlap
Changing implementation to use (start1 < end2 && start2 < end1) to
detect conflicts.

Lost stash of first implementation. This commit is reimplementing but
encounters exceptions.