Canonicalize our root path before we try using it, because we make assumptions about it not containing symlinks

Fixes #3242
add some debug to runtime.restore()
Merge pull request #3263 from tianon/abspath-root

Canonicalize our root path before we try using it
Merge pull request #3267 from vieux/debug_daemon_start

add some debug to runtime.restore()
prevent a panic with docker run -v /
Merge pull request #3268 from vieux/prevent_panic_volume

prevent a panic with docker run -v /
Move sqlite conn to graph db for cross compile support
Make Tianon the official root "Dockerfile" maintainer, since it's so hard-locked to hack changes most of the time
Use box-drawing characters in `docker images -tree`

This makes the output of `docker images -tree` look a little prettier.
Previously it displayed a combination of box-drawing characters and pipe
characters, so the lines didn't quite connect...

Before:

    └─aceb1e132fe5 Size: 487 MB (virtual 1.728 GB)
      |─c5480c55e00a Size: 44.89 MB (virtual 1.773 GB)
      | └─96c21b5e3c80 Size: 17.25 kB (virtual 1.773 GB)
      |   └─58f3f2293512 Size: 8.191 MB (virtual 1.782 GB)

After:

    └─aceb1e132fe5 Size: 487 MB (virtual 1.728 GB)
      ├─c5480c55e00a Size: 44.89 MB (virtual 1.773 GB)
      │ └─96c21b5e3c80 Size: 17.25 kB (virtual 1.773 GB)
      │   └─58f3f2293512 Size: 8.191 MB (virtual 1.782 GB)
Move root symlink check to engine.New

Since commit c91c365, when starting the docker daemon without an
existing /var/lib/docker directory, it fails with:

  2013/12/18 23:39:36 Unable to canonicalize root (%!s(*string=0xc210077c80)): lstat /var/lib/docker: no such file or directory

Move the symlink checking code to engine.New after the root dir has been
created.
Merge pull request #3270 from vreon/tree-box-drawing-characters

Use box-drawing characters in `docker images -tree`
Merge pull request #3275 from crosbymichael/sqlite-import

Move sqlite conn to graph db for cross compile support
Merge pull request #3277 from jpoimboe/fix-root-symlink

Move root symlink check to engine.New
Merge pull request #3274 from tianon/tianon-dockerfile

Make Tianon the official root "Dockerfile" maintainer
Allow host networking for containers