Tracking: feature/ui-improvements

[bradyzp]

Branch Tracking Issue for feature/ui-improvements

Overview:
This branch will focus on various usability improvements to the DGP user interface. Improving user interaction with the plotters, updating icons/visual elements, integrating work on user settings (persistent application state), etc.

Goals:

• Implement more user friendly plot controls for plotting data channels on different plots/axis' in line selection plot
• Integrate User Settings features, e.g. saving/restoring window position, improving recent-projects tracking/loading, restoring tabs to their last state (plotted lines etc)
• Add ability to hide/show segment selections on the LineSelectPlot
• Refactor workspace tab interface, create specific tab classes for different controllers (i.e. Project/Flight/DataSet).
• Add basic workspace tab state persistence, i.e. the plot tab will restore whichever series were plotted when it was last closed.

Future Branch:

• Implement custom UI Dialog for displaying formatted text e.g. for in-application help, graph-transform source etc. Similar to a QMessageDialog but with customizable central widget e.g. a QTextEdit or QTextBrowser
• Add option menu to plots enabling user to select the number of rows/columns (within limits) of plots to display. (may need to trigger a complete reload of the tab).