This adds several build targets to the project for doing all needed
steps for compilation.

Additionally, they are some schemes included which are intended
to be used for compilation:
- "Rebuild everything" builds all targets in the right order, including
  extras/tools, contribs, bootstrap, configure, make and make VLC-dev.

  This scheme should be used once to setup everything. For later
  builds, you should switch to the Make project scheme.
- "Make project" runs "make && make VLC-dev.app", to only recompile
  files if needed. Additionally, it creates a VLC-dev.app for testing.

The end result will be stored in the build folder set in Xcode. Both
VLC.app and VLC-dev.app can be accessed by using the "Build artifacts"
folder, and showing the files in finder.