Outsource build of module "action"
Outsource linking of module "command"
Outsource build of module "compositor"
Outsource build of module "connection"
Outsource build of module "input"
Outsource build of module "logger"
Outsource build of module "objects"
Outsource build of module "serialize"
Outsource build of module "util"
Outsource build of module "values"
Unify module inclusion in src/CMakeLists.txt
Rename frame_buffer.{c,h} to frame.{c,h}
Rename image_buffer.{c,h} to image.{c,h}
Rename wayland_buffer.{c,h} to buffer.{c,h}
Rename wayland_compositor{c,h} to compositor.{c,h}
Rename wayland_pointer.{c,h} to pointer.{c,h}
Rename wayland_shell.{c,h} to shell.{c,h}
Rename wayland_shell_surface.{c,h} to shell_surface.{c,h}
Merge pull request #296 from neithernut/cleanup-build_env

Cleanup build env
Fix command argument appending function

Previously we always returned the first element. Now we return the
last one (the one we just allocated), which was intented in the first
place.