* CMake: (fix) Changed names of the resulting config files.

Changed the name LibaecTargets.cmake, LibaecConfig.cmake and
LibaecConfigVersion.cmake to libaecTargets.cmake, libaecConfig.cmake
and libaecConfigVersion.cmake such that these files can be found
by cmake on a Linux machine.

* CMake: (feature) Better integration with HDF5.

- Changed the build such that always a static and shared library
  with be built.
- Rewritten CMake config files such that
  - One can select the shared or static library.
  - Set several libaec variables such one can, for example,
    check if the libaec library is found.
  - Set several Szip variables for the same reason as for
    setting the libaec variables. This is useful for a better
    integration with HDF5 when building HDF5 from scratch.