Merge pull request #392 from zkessin/master

Merging some contributer pull requests
Merge pull request #391 from fdevibe/charset-email-support

Add charset specification support to boss_mail.
cowboy server doen't start properly
fix cowboy static

thix fix depend on previous fix https://github.com/ChicagoBoss/ChicagoBoss/pull/393
add template error logging

ChicagoBoss/ChicagoBoss#379
Merge #394
Merge #393
fixed case
merge