Tired of committing around the generated version.prpoerties

file... so I'm remove it and fixing it with a .gitignore.

jme3-core/src/main/resources/com/jme3/system/.gitignore

@@ -0,0 +1 @@
+version.properties 

jme3-core/src/main/resources/com/jme3/system/version.properties

@@ -1,12 +0,0 @@
-# THIS IS AN AUTO-GENERATED FILE..
-# DO NOT MODIFY!
-build.date=2016-03-25
-git.revision=0
-git.branch=unknown
-git.hash=
-git.hash.short=
-git.tag=
-name.full=jMonkeyEngine 3.1.0-UNKNOWN
-version.full=3.1.0-UNKNOWN
-version.number=3.1.0
-version.tag=SNAPSHOT