Update README.md

Include a contribution section.
Update README.md

Include download, wiki, and issue section.
Initial gitignore commit.
Add exclusion rules.
License.
Reference gradle.properties values.
Include license notice.
Update build.gradle
Merge git://github.com/ShooShoSha/Craftable-Enchantments into ShooShoSha-release

Conflicts:
	.gitignore
	build.gradle
	gradle.properties
Merge branch 'ShooShoSha-release' into 1.7.2