Use wxMediaCtrl to play MIDI entries if no soundfont is set
- Added a basic 'first time setup' wizard, with pages to set up temp folder, base resource archives and node builders. May add more pages later. Also experimenting with using folder structure for source files, sources for the setup wizard are in src/Dialogs/SetupWizard
- Added ability to specify a custom temp folder, in case both system TEMP and the SLADE app folder are both restricted
Tweaked layout of dialogs to give extra border around the edges, just so they look a bit nicer and the ok button doesn't overlap the resize tab at the bottom right