pureikyubu 1.4

All Gekko caches are enabled by default, so there may be issues in games that used to work. To be fixed.

What's Changed

• Fixed step-over in Gekko debug (F10) by @ogamespec in #276
• Fixed locked cache by @ogamespec in #277
• User-friendly Debug::Halt by @ogamespec in #278
• DSP debugger is intergrated into common system-wide debugger by @ogamespec in #279
• Added imgui+SDL2 as submodules by @ogamespec in #283
• Cui + imgui by @ogamespec in #284
• Simplified uisimple.cpp by @ogamespec in #286

The debug console is ported for Linux using imgui (used by uisimple.cpp by default):

(thanks @edgbla for testing)