tests fixes and cleanup

run salmon's log server before tests execute, and shutdown after for travis testing
new setup_env.setup_router function
moved all test related handlers to salmon_tests.handlers
clear logs and run directories instead of deleting
encoding fixes

try extract charset from Content-Type header and encode content with that charset
set content encoding headers once in to_message function
nose for python 2.6 doesn't have assert_is_none tool function
Merge pull request #17 from hovel/tests

tests fixes and cleanup