Implements cli part for #542: Make logging configurable
Code review feedback
Use the LOG_LEVELS array that is already defined in Sensu
Merge pull request #589 from tomdz/master

Cli part for #542: Make logging configurable
added tests for cli log level, minor change to long argument for consistency
Merge pull request #590 from portertech/cli_log_level_tests

added tests for cli log level, minor change to long argument for consistency
[extensions] safe_run() as a catch-all, settings accessor and load_settings()
Merge pull request #591 from portertech/extensions

[extensions] safe_run() as a catch-all, settings accessor and load_settings()
[docs] updated changelog for 0.11.0 beta
Merge pull request #592 from portertech/docs

updated changelog for 0.11.0 beta
[udp] udp handler now binds to 0.0.0.0
[udp] updated changelog for 0.11.0 beta
Merge pull request #593 from portertech/udp

udp handler now binds to 0.0.0.0
add a more explicit note about breaking changes in extensions and mutators api
Merge pull request #596 from joemiller/master

add a more explicit note about breaking changes in extensions and mutators api
be more specific about only the extension interface changing.
Merge pull request #597 from joemiller/master

be more specific about only the extension interface changing.
[beta] version constant for 0.11.0.beta, changelog
Merge pull request #598 from portertech/beta

beta version, 0.11.0.beta
[redact] improved support for redacting sensitive client key values
         - clients may specify their own redact keys