[macro] Added thisfile and stem macros

- thisfile -> the properties file of the current processor
- stem -> provides the part before the extension
Do not expect bnd to export the libg packages
[maven] Updated the -pom command

The -pom now accepts “true”, “false”, or properties:

- groupid – The group id to use. When set, the artifactid=bsn by default. The default is the bsn prefix up to the last ‘.’.
- artifactid – The artifact id to use. Will use bsn if groupid is set. Otherwise default is last segment of the bsn.
- version – The version to use. Default is the bundle version
- where – The place where to put the pom. Default is “pom.xml”.


Signed-off-by: Peter Kriens <peter.kriens@aqute.biz>
Merge pull request #681 from pkriens/master

-pom stuff