Bump version to 0.16.1
Add a parameter for controlling pithcat's umask

Introduce the PITHCAT_UMASK option. This can be used to set the file
mode mask of the pithcat process.
helper: Exclude all tasks if no properties defined

If no image properties are defined, then do not run any configuration
task. Prior to this commit, the system would fail if no image
properties were present.
Update ChangeLog and version files for v0.16.1
Merge pull request #62 from skalkoto/hotfix-0.16.1

Hotfix 0.16.1
Bump version to 0.16.2
Fix a bash bug introduced in 64078dcb0ee954ba5d0d4
Do not verify the presence of img_properties

img_porperties is not a mandatory parameter for diskdumps any more.
docs: Add PITHCAT_UMASK in the sample config file
Update ChangeLog and version files for v0.16.2
Merge branch 'hotfix-0.16.2'
Merge branch 'master' into debian-trusty
Bump version to 0.16.2-1~trusty

Signed-off-by: Nikos Skalkotos <skalkoto@grnet.gr>