chore: add LCRE banner, SWF/ARC tools, ignore build artifacts

Replace README banner with LCRE-banner.png. Add SWF inspection
and ARC archive tools. Ignore compiled .class, .swf intermediates,
and staging directory in tools/.

README.md

@@ -1,4 +1,4 @@
-![Legacy Edition Banner](.github/banner.png)
+![Legacy Edition Banner](.github/LCRE-banner.png)
 # MinecraftConsoles (Legacy Console Revelations Edition)
 
 If you have any questions regarding this fork, this is my Fluxer server (similar to a Discord server):