N64 Support + bugfixes

Changelog:

• New "DOOM 64 (N64)" config that will create and save maps that can be used with ROM hacks to compile custom DOOM 64 ROMs with custom maps. More info on DOOM 64 modding on N64 here: https://docs.google.com/document/d/1i9rDwRTwiKMfXOWNv8b3eUr12sByJoxCSF5OaivBCsM/edit#heading=h.c8cox3uqez3
• New "Convert PC Map to N64 Map" config that serves as an (arguably hacky) easy way to convert an existing DOOM 64 map for PC to DOOM 64 map for N64. Simply open the map using this config and click Save (if you wish to preserve the original PC version, then use Save As) to convert the map. You can then open it again in the "DOOM 64 (N64)" config to continue editing it.
• Some leftover bugfixes related to window changes from last patch

Credits:
Thank you to @azamorapl for getting DOOM 64 custom maps to run on N64, whose work was used for this patch.

EX+ support + UI fixes

Changelog:

• Added a new EX+ specific map configuration which allows you to place enemies and linedef actions unique to the EX+ source port
• Fixed some buttons in the Edit dialogs not working
• Rearranged action linedefs so that they are ordered more logically

Performance Improvement in Visual Mode

Changelog:

• Fixed performance regression in Visual Mode. FPS in Visual Mode should increase by at least 30 %.
• Added an option to enable an FPS counter in Visual Mode. The option is located in Preferences/Appearences -> Show FPS in Visual Mode

Doom Builder 64 1.5 - Huge UI Update

Changelog:

• Brought linedef, sector, and thing edit windows into the 21st century (no more tabs)
• Added button to auto align textures in X and Y axis at the same time (Ctrl+A)