gradle.properties is only commented out defaults, so remove from git

For anyone who tweaks this file for local settings, it becomes painful
to have it committed in git because those changes which are only
relevant to the local setup will show up in git as changed.

.gitignore

@@ -7,3 +7,4 @@
 /app/app.iml
 /.idea
 /*.iml
+gradle.properties

gradle.properties

@@ -1,18 +0,0 @@
-# Project-wide Gradle settings.
-
-# IDE (e.g. Android Studio) users:
-# Gradle settings configured through the IDE *will override*
-# any settings specified in this file.
-
-# For more details on how to configure your build environment visit
-# http://www.gradle.org/docs/current/userguide/build_environment.html
-
-# Specifies the JVM arguments used for the daemon process.
-# The setting is particularly useful for tweaking memory settings.
-# Default value: -Xmx10248m -XX:MaxPermSize=256m
-# org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
-
-# When configured, Gradle will run in incubating parallel mode.
-# This option should only be used with decoupled projects. More details, visit
-# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
-# org.gradle.parallel=true