EA-21 - Encountertransaction API compatibility with OpenMRS 1.10

Provide basic compatibility with OpenMRS 1.10. This does not use the new API - revise, discontinue etc right now. We were thinking of doing this as part of another sprint soon. 
Using "target/" instead of multiple entries - /target, api/target etc will make the .gitignore files shorter, and extend for new projects that we add. This is similar to what we have in openmrs-core - https://github.com/openmrs/openmrs-core/blob/master/.gitignore