Fixes for receive_email pipe script and Whenever

[mrtorrent]

These commits fix the following:

• receive_email script breakage if not specifically run from the Rails root
• typo in output redirection in receive_email script which could inadvertently generate a bounce message
• old version of Whenever doesn't work with Bundler
• Whenever config is broken (tries to call a Rails method)
• extraneous cron job for mail:inbox will fail if using pipe method
• Sphinx cron job incorrectly rebuilds rather than reindexing

[mrtorrent]

Several more fixes. I'll apply these to the dev branch in a minute as well

[mrtorrent]

Added a fix for output redirection in the receive_email script to prevent bounce messages