0.1.0git
add a variable `:mvn_roles' to setup task roles
use :mvn_target_path and :mvn_target_path_local
use `_merge_environment` to generate environment
create enclosing directory on mvn:update_settings_locally
test :mvn_release_build on remote servers
update develop dependency of capistrano-jdk-installer
JVM args should not join with ":".
update README
release 0.1.0

* setup PATH and JAVA_HOME in :default_environment
* add `mvn.exec()` method to invoke Maven.
* not download archive as many as servers. download just once and then
  distribute it.
* :mvn_update_remotely and :mvn_update_locally are not not exclusive
* add test cases
Merge branch 'release-0.1.0'
Merge branch 'master' into develop
0.1.1git