feature(fabric): added fabric support (#491)

* Initial work towards Fabric compat. This does not compile yet

* Further updates - should compile but Gradle is being weird.

* Remove useless buildscript extras

* Added mixins to buildscript classpath to fix Loom crash

* Make it compile

* Got it building and added interaction

* Fixed review comments

* Use ServerPlayerEntity for FakePlayer

* Use method references for nicer names

* Fixed remaining comments and added networking for CUI

* Output as dist.jar

* Added mixins for left click air

* Use regex for cleanliness

worldedit-fabric/src/main/resources/worldedit.mixins.json

@@ -0,0 +1,13 @@
+{
+    "required": true,
+    "package": "com.sk89q.worldedit.fabric.mixin",
+    "compatibilityLevel": "JAVA_8",
+    "mixins": [
+        "MixinServerPlayerEntity"
+    ],
+    "server": [
+    ],
+    "injectors": {
+        "defaultRequire": 1
+    }
+}