Doctor Filter

Added a filter using only a textbox that filters the doctor column
Added Multiple Filtering

Added Multiple filtering between Doctor and Patient.
Multi Filtering all fields except Date

Added Filtering functionality between all fields excluding date. Date
throws an exception due to the formatting and I haven't gotten to it
yet.
Added Date Filter

Added the final piece of multi filtering. Also set the default date to
the current date.
Merge pull request #16 from galitskyd/Multi-Filter

Multi filter