added BundleCollection

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
allow to set MkdirAll and Symlink errors on fake file system

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
introduce Applier object to set up jobs and packages

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
add missing assertion for unmount_disk

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
correctly stay backwards compatible with ruby agent ApplySpec

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
made Symlink method implement "ln -sf"

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
added idempotency test for MkdirAll

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
make sure that install/enable dirs exist

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>