Keep x-axis range the same when changed
Make x-axis type persistent
Merge pull request #7 from crwper/fix_bottom_axis

Fix bottom axis
Added shortcuts for x-axis options
Merge pull request #8 from crwper/x_axis_shortcuts

Added shortcuts for x-axis options
Added 'zero here' tool
Added 'set ground' tool
Merge pull request #9 from crwper/add_zero_tool

Add 'set zero' and 'set ground' tools
Made icon larger
Merge pull request #10 from crwper/update_icon

Made icon larger
Change 'zero' to 'exit' and update shortcut key.
Merge pull request #11 from crwper/change_menu_text

Change 'zero' to 'exit' and update shortcut key.
Fixed getAbove and getBelow functions
Merge pull request #12 from crwper/fix_bugs

Fixed getAbove and getBelow functions
Added new values to plot types
Changed x-axis titles and values to PlotValues
Merge pull request #13 from crwper/move_x_axis_to_class

Move x axis to class
Added new values and menu items
Fixed a problem with numSV interpolation
Changed colour for numSV plot