Fix editor scaling

[NebelNidas]

• The editor font actually scales now. It didn't before because of multiple reasons:
  • editor.setFont was called too early. In this state, the editor doesn't have a font applied, so the system default (non-monospaced!) is returned.
  • This didn't matter though, since editor.setContentType("text/enigma-sources") overwrote it anyway with the DefaultFont property defined in EnigmaSyntaxKit (making the DEFAULT_FONT reflection hack redundant, no idea why that existed).
  • DefaultFont is usually set to UiConfig.getFallbackEditorFont(), which intends to scale the default monospace font to the current DPI settings.
  • This didn't work either though, as BasicTweaker#modifyFont only scales UIResources, which Font is not a subclass of.
• Highlight boxes are now scaled correctly too.