Update version, authors and changelog for 0.1.1
Correct CMake module name

Current(incorrect):

CMake Warning at CMakeLists.txt:292 (FIND_PACKAGE):
  By not providing "FindSDL_TTF.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "SDL_TTF", but
  CMake did not find one.

  Could not find a package configuration file provided by "SDL_TTF" with any
  of the following names:

    SDL_TTFConfig.cmake
    sdl_ttf-config.cmake

  Add the installation prefix of "SDL_TTF" to CMAKE_PREFIX_PATH or set
  "SDL_TTF_DIR" to a directory containing one of the above files.  If
  "SDL_TTF" provides a separate development package or SDK, be sure it has
  been installed.

Expected(correct):

-- Found SDL_ttf: /usr/lib/libSDL_ttf.so (found version "2.0.11")
Update Authors + changelog
Added isSetVisible() to the Widget class. It's very similar to isVisible() but ignores the parent.
Added the possibility for horizontal scrolling. See https://github.com/fifengine/fifengine/issues/687
As first the bar visibility is used to decide the scroll direction, if both are visible then the one with the larger scroll size is used.
Update version, authors and changelog for 0.1.2
Created GuiDeathListener. That should prevent crashes if the widget is hidden and removed on the same pump.