add scala-maven-plugin support

Add goals for Maven Scala [1] plugin.

[1] http://davidb.github.io/scala-maven-plugin/

Author: agebhar1

bash_completion.bash

@@ -183,6 +183,7 @@ _mvn()
     local plugin_goals_spring_boot="spring-boot:run|spring-boot:repackage"
     local plugin_goals_jgitflow="jgitflow:feature-start|jgitflow:feature-finish|jgitflow:release-start|jgitflow:release-finish|jgitflow:hotfix-start|jgitflow:hotfix-finish|jgitflow:build-number"
     local plugin_goals_wildfly="wildfly:add-resource|wildfly:deploy|wildfly:deploy-only|wildfly:deploy-artifact|wildfly:redeploy|wildfly:redeploy-only|wildfly:undeploy|wildfly:undeploy-artifact|wildfly:run|wildfly:start|wildfly:shutdown|wildfly:execute-commands"
+    local plugin_goals_scala="scala:add-source|scala:cc|scala:cctest|scala:compile|scala:console|scala:doc|scala:doc-jar|scala:help|scala:run|scala:script|scala:testCompile"
 
     ## some plugin (like jboss-as) has '-' which is not allowed in shell var name, to use '_' then replace
     local common_plugins=`compgen -v | grep "^plugin_goals_.*" | sed 's/plugin_goals_//g' | tr '_' '-' | tr '\n' '|'`