Updated bbb-fsesl-client project to use sbt 1.2.6 and scala 2.12.7

bbb-fsesl-client/build.gradle

bbb-fsesl-client/build.sbt

bbb-fsesl-client/deploy.sh

bbb-fsesl-client/project/Build.scala

bbb-fsesl-client/project/Dependencies.scala

bbb-fsesl-client/project/build.properties

bbb-fsesl-client/project/plugins.sbt

...st/java/org/freeswitch/esl/client/inbound/ClientTest.java