[Android] Refine the callback function of compressor.

This patch is to refine the feature of compressor.
Due to optparse store the converted value when we use '--compressor'
at the first time. Now add 'type' and 'nargs', it instructs optparse
to consume the argument and convert it to type.
Add test case for this feature.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1151