Added <options/> support to Proguard configuration

Additional Proguard options can be added using an <options/> element,
allowing to configure the plugin in a super POM.
The classes inside classes.jar have been extracted.

Don't add them twice.
Fixed checkstyle error when building.

Unused import.
issue-174: created helper method for checking META-INF matches
issue-174: allow entries specified by <metaIncludes/> to be unpacked
issue-174: refactored to use the meta-inf matcher method
issue-174: walk through the whole class hierarchy to retrieve annotated
fields
issue-174: new POJO to configure META-INF patterns
issue-174: use new MetaInfo pojo for configuration
issue-174: ConfigHandler should set NULL value if no method specified
for non required parameters
issue-174: added helper methods for tests to MetaInf
issue-174: added MetaInf configuration to UnpackMojo
issue-174: added tests for UnpackMojo
issue-174: one more assertion
issue-174: restored from master
issue-174: restored spacing
issue-174: restored spacing
issue-174: updated @author
fix: use parsedOptions instead of proguardOptions
Create a copy of manifest file and use it further.

Old mojo updated the original manifest, which could create issues if
the plugin is bound to the build process, especially during releases.

The new approach allows to create a copy of the manifest (usually
${project.build.directory}/AndroidManifest.xml) and use it to create
the APK.

This creates the possibility to use buildnumber-maven-plugin or other
extension if desired.