Merge pull request #250 from Ocramius/feature/gitattributes

Lightweight export as of doctrine/doctrine2#543

.gitattributes

+/tests export-ignore
+/docs export-ignore
+.gitattributes export-ignore
+.gitignore export-ignore
+.gitmodules export-ignore
+.travis.yml export-ignore
+build.properties export-ignore
+build.xml export-ignore
+phpunit.xml.dist export-ignore
+run-all.sh export-ignore
+composer.lock export-ignore