HepMC2-2.06.11-bp153.1.18

- Update to version 2.06.11:
  * HepMC/HepMCDefs.h: Add a HEPMC_HAS_ORDERED_WEIGHTS #define.
  * HepMC/WeightContainer.h: Add weights() and weight_names()
    public methods.
  * src/WeightContainer.cc: Fix print() to use canonical weight
    ordering.
  * src/GenEventStreamIO.cc: Fix the I/O streaming to preserve the
    weight ordering.
  * Fixed the tests.
- Use %license for COPYING file.
- Minor updates to spec file.
- Update URL and Source Url to new upstream website.

- Trim description for size (like was already done for HepMC
  1st Generation).

- Fix shared lib Group, should be System/Libraries.

- Add explicit Conflicts between HepMC2-devel and HepMC-devel > 3,
  make HepMC2-devel provide HepMC-devel = %{version}.

- Adapt to using HepMC2 as package name.

- Initial version (copy from HepMC = 2.06.09).