Add log dir to repository as new Thinking-sphinx requires it
Add app/log to see if it helps new sphinx to run at heroku
Downgrade thinking-sphinx 3.0.6 -> 3.0.4 to avoid strange log problem

see: http://support.flying-sphinx.com/discussions/problems/1177-heroku-error-when-deploying-thinking-sphinx-gem-304-no-such-file-or-directory-tmpbuild_xxxlog
Now really change the thinking sphinx version (as tried earlier)
remove unnecessary log dir
Merge branch 'master' of github.com:sharetribe/sharetribe