patched config loader to use toml.PrimitiveDecodeStrict when loading
plugins
fixed some old TOML files that still referenced message_filter
removed the outputs param from TOML tests
added tests for common parameters that aren't part of a struct
Merge branch 'dev' into features/issue_124

Conflicts:
	pipeline/config_test.go
use reflection to extract the fields from PluginGlobals struct
Merge pull request #266 from mozilla-services/features/issue_124

Features/issue 124