implemented inject headers
Renamed injectedHeaders to additionalRequestHeaders when adding request headers to proxy stubs, and made corresponding ResponseDefinitionBuilder calls typesafe (can only be called after proxiedFrom(...).
Added doc note about adding headers when proxying
Updated docs
Added exclusions to Maven standalone config example in docs
Fix for issue #193 causing NPE to be thrown when recording enabled programmatically
Merge branch 'master' of https://github.com/tomakehurst/wiremock into rotating-request-journal

Conflicts:
	docs/source/getting-started.rst
	src/main/java/com/github/tomakehurst/wiremock/core/WireMockConfiguration.java