Fixes improvement https://issues.jenkins-ci.org/browse/JENKINS-18361:
- Exposed subbuild info through remote API and environment variables.
- Corrected how environment variables were being injected
- Minor tweaks to the envrionment variables that are injected
Removing unnecessary imports and addind javadoc for new private method for injecting env vars
Merge pull request #1 from dkichler/export-sub-build-info

Export sub build info