API, modularization, general cleanup (#362)

* Move customizable generator to new repository, rerganize the code, put API into api source set

Fix cubic chunks mixin config packages

Put API back into main mod, update gradle

API as separate repository doesn't really work if the API depends on MC as
forgegradle puts fml annotation cache json into the jar.
And when the API jar is shaded into the mod, FG finds a duplicate entry.

* Move coremod class to new package so that runtime deobf works on mixin classes

* Fix precipitation height using z coordinate twice

* Fix another reference to old coremod package name

Author: Barteks2x

.travis.yml

@@ -20,10 +20,12 @@ before_install:
 script: ./gradlew clean build
 deploy:
   - provider: script
-    script: "./gradlew clean uploadArchives"
+    script: "./gradlew clean publish"
     skip_cleanup: true
     on:
       repo: OpenCubicChunks/CubicChunks
+      # check the branch with regex to match master and MC_version branches
+      condition: $TRAVIS_BRANCH =~ ^(master|MC_([0-9]+\.)+[0-9]+)$
       all_branches: true
 
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