Update the message header to include optional hmac information
Merge branch 'dev' into features/message_signing
Merge in the dev branch and add tests for message signing

The config should look like this
[TCP:5565]
type = "TcpInput"
address = "127.0.0.1.5565"
    [signer.trink_0]
    hmac_key = "4865ey9urgkidls xtb0[7lf9rzcivthkm"
Clean up duplication in unit test code
Add signer verification to the message matcher
Update flood to support message signing

- Moved the flood configuration into a toml file (the command line
options were becoming too numerous).  Various sections can be created
and referenced by name so it can store all the test configurations
Add sandbox_manager_filter for dynamic control of sandbox filters

- start/stop functionality only (messages will be missed during
the cycle).  Replace (no message loss) will have to be pushed out
to the next release

- sbmgr allows a user specified sandbox to be loaded/unloaded
- sbmgrload allows a number of instances of a hard coded sandbox to
be loaded/unloaded
Merge branch 'dev' into features/message_signing

Conflicts:
	pipeline/config.go
	pipeline/inputs_test.go
	pipeline/mock_outputrunner_test.go
	pipeline/mock_pluginhelper_test.go
	pipeline/pipeline_runner.go
Don't leak pipeline configs btn tests, remove unnecessary selects.
re-add the explicit "ok" check.
Remove `getTestPipelinePack` since it isn't useful in the general case w/o leaking
PipelineConfig setup btn test environments.
Fix TCPInput exit issues

- Read error no longer infinitely loops
- Run will not exit until all handleConnection routines are finished
Merge branch 'features/message_signing' of github.com:mozilla-services/heka into features/message_signing
Move test utilities into their own subdirectory

- use a named return for err
Incorporate review feedback

- update docs
Merge branch 'dev' into features/message_signing

Conflicts:
	testsupport/mock_net_conn.go
Use the Helper interface to access the FilterRunner
Merge pull request #87 from mozilla-services/features/message_signing

Features/message signing