Added PreferencePane initial version
Added error messages for redundant scratchwork columns
Added notational settings options - working for TFTestButton and QTestButton
Adding prompt text for adding new columns
Fixed a bug with incorrect operator precedence
Program now displays error when adding scratchwork columns before target.
Merge branch 'master' into wffchecker-future
PreferencePane working properly
Merged master in
Added tooltips for buttons
Added defaults button to preferences
Added nonfunctional delete buttons
Merged master into branch, fixed conflicts