Release Evaluator 2.1.0

What's Changed

• v2.1.0 snapshot by @mdnazmulkarim in #145
• Removing heavy resources from the main fhir lib by @vitorpamplona in #143
• Update the evaluator to use the 2.1.0-SNAPSHOT engine by @brynrhodes in #147
• Use the cql-engine's ExpressionResult API by @JPercival in #150
• add sde list fixture and test by @mdnazmulkarim in #149
• Unique contained evaluated resource test by @mdnazmulkarim in #152
• Formalizes compliance with Android 8, SDK 26 (2017+) by @vitorpamplona in #157
• Uses a fluent interface for test case utility classes of plan definition by @vitorpamplona in #153

Full Changelog: v2.0.0...v2.1.0