* If the ABI is unstable, making the SONAME equal
  to the PROJECT_VERSION at least allows packagers
  to notice when potential breakage is about to occur.

* The manpage is tiny, and distributions will
  recompress the manpage into a different
  format anyhow.

* Use `GNUInstallDirs` as it allows changing
  of all dirs in a standardised, Kitware
  supported way. `LIB_SUFFIX` is not idiomatic
  and not supported by Kitware:

    http://kwwidgets.org/Bug/view.php?id=10287

* Use ISO C++11 over the GNU variant, as this
  makes cross-platform porting efforts easier
  to other compilers.
* Don't search for a C compiler, speeds up
  configure step.
* Use proper idiom to change `CMAKE_INSTALL_PREFIX`
  default:

    https://cmake.org/cmake/help/latest/variable/CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT.html

closes #56