Create a backburner connection per thread (#47)

Signed-off-by: Tristan Crockett <tristan@leadkarma.com>
Print full original backtrace when rescuing from timeout
added ability to set per-queue default ttr's
Merge pull request #51 from ryanjohns/queue-respond-timeout

added ability to set per-queue default ttr's
Bump to 0.4.4 and add changelog
Update README.md
Updating delayed section
Merge pull request #48 from thcrock/master

Create a beanstalk connection per thread (#47)
Add to changelog
Bump to version 0.4.5