Bugfix: shared library link names are incorrect

Bugfix: shared library link names are incorrect

The standard link names are:
  libfake.so -> libfake.so.0
  libfake.so.0 -> libfake.so.0.5.0

Instead, I had:
  libfake.so.0 -> libfake.so.0.5
  libfake.so.0.5 -> libfake.so.0.5.0

While I am at it, make these links reflect the version_target setting.
If target is major, then standard link names above are followed.
If target is minor, then:
  libfake.so -> libfake.so.0.5
  libfake.so.0.5 -> libfake.so.0.5.0
If target is micro, then:
  libfake.so -> libfake.so.0.5.0