Make a helper function to retrieve history instances.
Make a helper function to retrieve all history events.
Move the SQL input sanitization code into its own function.
Create the SearchHistory function. This should complete the necessary changes in User.cs.
Initial attempt to connect search functions to GUI for history.
Make results actually  appear when performing a history search.
Add mechanism to make the checkbox for showing only current medical events work.
Populate the history tab when a patient is selected.
Clear up a couple warnings.
Fix the History tab columns.
Modify history search a bit (main change: remove support for searching by history event code).
Remove unused variable.
Only show history results for the selected patient.
Refresh the History tab when toggling the checkbox for only showing current events.
Some code rearrangement and minor changes.
Make the History tab search button functional.
Merge in the history_tab branch.