Gradle Improvements

So I've decided to help you out some some minor Gradle improvements. I touched the code in one place; you'll see.
* Re-formatted the gitignore to make it look nicer and added eclipse files
* The buildscript has been improved a lot
  * Waila is now downloaded automatically on setup and is added to the classpath. No more manual download! I left the libs folder in the gitignore just in case.
  * There is now a `build.properties` file containing the essential numbers. This minimizes the need to tamper with the `build.gradle` file.
  * On build, the version number in the code is replaced, much like the token replacement that was in ant. Now you only have to change the version number in one place! (On build, the version in the JAR name will have the MC version in it, but the in-game version of the mod won't. You can change that if you'd like)
  * Also bumped Forge to latest recommended build and the Gradle wrapper to 1.12 while I was at it. (I had to chmod `gradlew` in order to use it).