[Reviewer: Matt] Add headers to the HTTP compression profile

Adds HTTP headers to the HTTP compression profile. I have not bumped the resource bundle version as we are not using compression right now (though we should bump it when we enable compression). 

I have tested this by:

* Checking that sprout builds OK. 
* Feeding the dictionary into the sas-client UTs and checking they run successfully. 
* Checking in vim that the string matches the version in clearwater-sas-resources. 
As just discussed, Chronos doesn't support UTF-8 but we've dug around and nothing needs to use that yet.  Please can you raise a low-priority (enhancement?) issue to cover this?