Add indexCreate example for issue #255

Also fixes a couple typos
Fix uncaught typos
Change ( ) to [ ]
Update index_create.md
Use block, not r.row
Merge remote-tracking branch 'upstream/master'
Change "an ReQL" to "a ReQL"
Merge pull request #273 from chipotle/master

Add indexCreate with multi index and ReQL expression example -- PR by @chipotle