Merge pull request #29 from deverton/master

Bump version for release to 0.13.5
Add support for multiple log appenders (as introduced in dropwizard 0.7.0)
 - see https://dropwizard.github.io/dropwizard/manual/core.html#id4
 - old format is still supported for now, but deprecated
Update README to match new log config format
Remove obsolete methods
Extend logging to support filtered appenders
Merge pull request #32 from BMFraser/expand-logging-options

Expand logging options
Bump version for release to 0.13.6
Merge pull request #33 from BMFraser/release

Bump version for release to 0.13.6