0.8.1/fix num_threads issue


I made a minor release of SequenceServer, 0.8.1, to address the
num_threads issue brought up by Robin and Matthias [1]. Just run `gem
install sequenceserver` on the command line to make your SS
installation multi-core capable.

Initially the plan was to push the fix in the 0.9.0 release which is
taking some time. Hence the delay.


[1]: https://groups.google.com/forum/?fromgroups=#!topic/sequenceserver/eNP1vmL58D4