Hotkey Editor Polishing

Refactor hotkey editor to use tab control instead of one giant list.
Each tab is a separate hotkey section.
Modify EDA_HOTKEY_CONFIG to change the m_Comment member to m_Title for a new purpose.
We want a pretty title in the hotkey editor. We use m_Title for the key export comment which
still conveys the purpose just as easily.
Refactored usage of wxGrid into wxListCtrl which allows capturing navigation characters
and also works better (single selection is built in).
Add hotkey overwrite prompts that are paired with "Common" section. It will check if a hotkey
overlaps with the proper sections. i.e. Common with the all other sections; or Section 1 with just Common.
Right-click menu removed due to wxListCtrl being able to catch the special keys properly.
Make hotkey command titles use consistent capitalization.
Rename "Switch highcontrast" to "Toggle High Contrast".
Eliminate most of the abbreviated hotkey titles.
Doxygenize dialog_hotkeys_editor.h and add missing license block.
Display <unassigned> if key code is 0 (NULL).
Fix hotkey editor on Windows not using max height of the dialog for the list control.
Set wxNO_BORDER for the tab page.
Hot key editor dialog improvemnts.

* Change hot key editing contol from wxGridTableBase to wxListCtrl.
* Separate hot key lists into separate tabs rather than one large list.
* Coding policy fixes.