Removed no-op window close callback.

The window close flag is already set before the window close callback is
called.
Set final window title right away.

There is no need for a separate call to glfwSetWindowTitle.
Removed setting window hint to default value.

GLFW 3 has sane defaults for all hints.  The default for the depth bits
hint is 24.
Disabled building of GLFW examples and tests.
Removed dependency work already performed by GLFW.

The GLFW CMake files already find and export the GLFW_LIBRARIES variable
that contains all dependencies needed by GLFW, GLEW and the samples.
Removed bundled GLEW makefile replaced by CMake.

CMake will overwrite the bundled GLEW makefile with its own each time it
generates files, leading to an unclean Git tree.
Enabled internal versions GLEW and GLFW on OS X.
Disabled -fpermissive compiler flag on OS X.

The flag is not supported on OS X and caused warnings.
Enabled debug output callback on OS X.

It is used by the samples and does not use anything not available on OS
X, so there is no need to disable it during compilation.
Removed superfluous link_directories call.

The add_dependencies and target_link_libraries calls set up all
necessary links between the projects.
Removed duplicate inclusion of GLFW header.
Merge pull request #20 from elmindreda/master

Various GLFW and build fixes