Forbid certain paths within docker build ADD

Conflicts:
	buildfile_test.go
change network range to avoid conflict with EC2 DNS
Change daemon to listen on unix socket by default

Conflicts:
	docs/sources/api/docker_remote_api.rst
Bump to v0.5.2
Merge pull request #1464 from dotcloud/bump_0.5.2

Bump to 0.5.2