Expose additional thread pool options (OHDSI#1420)

Removed modification of string_val column (OHDSI#1155) (OHDSI#1397)

Upgrade Impala driver to 2.6 (using JDBC 4.2) (OHDSI#1340)

* Use released version of standardized-analysis-utils

* Increase WebAPI version to 2.7.4

* Upgrade Impala driver to 2.6 (using JDBC 4.2)

* Fixes batch mode

Specifies non-snapshot arachne-commons version

Updates circe to newer release which resolves PLE issues on Impala

Pom update: use released components in pom.xml (OHDSI#1216)

Release v2.7.1

Release v2.6.0

Update pom references