Updating other directories in gitignore file to start with a slash

This ensures that only the directories in the repo home are ignored

Author: Mark Grover

.gitignore

@@ -1,17 +1,17 @@
-dist/
-build/
+/dist/
+/build/
 annotation-plugin.jar
 .factorypath
 .classpath
-docs/
+/docs/
 input
 /lib/
-report/
+/report/
 ivy/*.jar
 ivy/pom.xml
-test-output/
+/test-output/
 .pigunit-input-overriden.txt.crc
 pigunit-input-overriden.txt
 *.asc
-bin/
+/bin/
 .ant-targets-build.xml