Update build-and-push.html

Fix spacing
Update build-and-push.html

Update spacing.
Pointing latest release to 1.6 zip on github
Update quickstart.html

Adding one more usage line for "help" command in client shell
adding voldemort admin tool page
Update default.html
Update default.html
update documentation related to gradle

Modified some of the ant related documents to gradle
Added few of the typical gradle build commands