Initial work on #106.

Moved the load order preview window to a new header/source file, and cut
out the move up/down buttons. Started to implement mini editor.
MiniEditor layout and plugin list work.
GUI code refactoring.

Helper dialogs and controls are now in misc.h/.cpp, and the MiniEditor
class got moved into editor.h/.cpp.

Also , the Editor class now takes plugin lists, not vectors, to match
the rest of the code. The alpha sort function had to be updated to
invert the order, to give the same result.
Editor code refactoring.

Also minor edits to MiniEditor and Editor:
* MiniEditor now reconstructs plugin metadata using the original
metadata for everything that's not got a control.
* MiniEditor's Load After control now holds all related metadata, but
only the filenames are visible by default to keep things simple.
* The Editor and MiniEditor windows are now resized to fit the filename
text, and their lists' columns are resized whenever new metadata is
loaded into them.
MiniEditor tweak.

Plugin priorities in the plugins list now get updated when a new plugin
is selected. Also fixed bolded entries for plugins that have been edited
being unbolded by the filter.
#106. Implemented drag 'n' drop in mini editor.
Moved some of the launcher functions around.
Updated metadata editor launching code.

Now uses lists instead of vectors, as required.
Fixed new dialogs not closing.
Started to implement changes to sorting.

Haven't got the loop or the edge deletion in yet, but everything else is
there, I think.
This should clear edges fine.

Not entirely sure about what iterators get invalidated when.
Sorting process updated.

Behold the infinite loop!
Obliterated load order preview dialog.

Now the mini editor dialog has its editing part hidden until a plugin is
selected. Need to add some text to the dialog still to explain what it's
for.
Mini editor filter fixes.

Stopped flickering on toggle, and selection of other plugins is now
disabled while the filter is active.
Fixed text formatting in mini editor.
Mini editor filter improvements.

Now doesn't fight with the plugin addition toggle. Also now displays
only those plugins that the selected plugin can validly load after, and
displays plugins that have a BSA that may contain conflicting resources,
if the selected plugin has a BSA.
Removed "Add Plugins" toggle from mini editor.

The filter checkbox now has the same effect, so it's unnecessary.
Mini editor drag 'n' drop improvements.

Now doesn't do anything if you try to add the selected plugin or a
plugin that's already listed in the box.
Updated text in mini editor.
Attempting to fix the layout of the mini editor.

Made the editor non-resizable to keep things simple, initially wrapping
dialog text to width of plugin list. Selecting a plugin with a long name
seems to resize the editingPanel right, but it then gets clipped by the
dialog window, which doesn't resize correctly.