Ignore cleanup with /dev/mapper does not exist
Use incrementing prefix on pool and loopback to allow dind
Make sure the base device is well created before running the tests
Rename loopback dir to devicemapper
Add filesystemtype for containers

If no type is specified then assume aufs.
Merge pull request #2227 from dotcloud/dm-rename-loopback

Rename loopback dir to devicemapper
Merge branch 'dm-fix-test-2' into dm
Merge branch 'dm-missing-mapper' into dm
hack: only run certain tests with TESTFLAGS='-run TestName' make.sh
hack: don't set DEBUG when running tests
Merge branch 'dm-base-hash' into dm
Merge branch 'dm-refactor-init' into dm

Conflicts:
	runtime_test.go
WIP: debugging dm-base-hash + dm-refactor-init