libsilk

Merge pull request #3 in SD/libsilk from ~S3RJ1K/libsilk:master to master

* commit 'e111aee91d84d9ccf124ccb5f73352e663d78b4f':
  proper library versioning
  update silk to 1.0.9, fix build on debian 8
  FS-7553: build_rpm.sh allow build only SRPM