Add preserve_data to the sandbox decoder
Added the preserve_data option to the sandbox decoder documentation
let decoder implement WantsName interface
data preservation test
update CHANGES.txt
Merge branch 'dev' into sandbox_decoder_preserve_data

Conflicts:
	docs/source/sandbox/decoder.rst
	sandbox/plugins/sandbox_decoder.go
	sandbox/plugins/sandbox_filter.go
Merge branch 'dev' into sandbox_decoder_preserve_data
Minor test cleanup
Merge pull request #688 from mozilla-services/sandbox_decoder_preserve_data

Sandbox decoder preserve data