Refactored editor config references.
Added `editor.foldtype` with box, cirle, arrow, and plus types (ref #305).
Increased default font size in the editor (ref #305).
Added explicit conversion to number for numeric settings.
Made fold and marker margins wider (ref #305).
Added `editor.extraascent` option to add line spacing (ref #305).
Improved compatibility with wxwidgets 2.8.
Updated breakpoint/currentline markers for less contrast colors (ref #305).
Added `editor.foldflags`; set default to draw one line when folded (ref #305).
Added wrapped line indicator to line number margin (ref #305).
Added `outputshell.usewrap` to set Output wrapping; on by default (ref #305).
Set def linenumber font size as one smaller than editor font size (ref #305).