Upgrade to the Maven Invoker plugin version 1.7

Release Notes - Maven 2.x Invoker Plugin - Version 1.7

** Improvement
   * [MINVOKER-135] - log relative script path instead of full script
path for pre-/post-build scripts
   * [MINVOKER-136] - upgrade groovy version used to 2.0.1

** Task
   * [MINVOKER-134] - use maven-plugin-tools' java 5 annotations

Release Notes - Maven 2.x Invoker Plugin - Version 1.6

** Bug
    * [MINVOKER-112] - duplicate script classpath entries are not
filtered out, can cause ClassCastException

** Improvement
    * [MINVOKER-101] - provide property to make a clean clone
    * [MINVOKER-108] - Upgrade doxia and doxia-site-tools version to 1.1.4
    * [MINVOKER-109] - upgrade maven-reporting-api and
maven-reporting-impl versions
    * [MINVOKER-111] - plugin is now 1.5 minimum
    * [MINVOKER-113] - update to Groovy 1.7.5 (from 1.5.6)
    * [MINVOKER-116] - Mark plugin as @threadSafe
    * [MINVOKER-120] - Move various script interpreters to a new
artifact in maven-shared
    * [MINVOKER-129] - Code cleanups
    * [MINVOKER-130] - Add a reference to the buld-job documentation
    * [MINVOKER-131] - upgrade groovy version used to 1.8.6

** New Feature
    * [MINVOKER-97] - Add possibility to inherit settings.xml from
calling process
    * [MINVOKER-102] - Provide a way to install Extra dependencies
    * [MINVOKER-110] - It tests must be runnable in parrallel

** Task
    * [MINVOKER-103] - Update to plexus-utils:2.0.4+ to eliminate
deadlock potential during forked Maven executions
    * [MINVOKER-128] - Remove old workaround for MINVOKER-50 in POM