Fix issue #34:
  * change the `osgi.versionpolicy` to generate version range import from a given major.minor.micro to the next major. By the way this is the default bnd lib behavior.
  * remove extract version property in the export statement as it is just the default bnd lib behavior and therefore does not add value except make it explicit
   * remove the `osgi.import` properties has the default bnd lib behavior provide exactly the same and also ensure that the import statement will be always in sync with the dependency usage.
Merge pull request #47 from javabits/34

Fix issue #34: OSGI import statement version range management