Merge pull request #641 from kylog/maint/update-contrib-docs-for-target-branch

(maint) Update docs to reflect use of facter-2 branch
(FACT-234) Add blockdevice uuid fact

Add facts to show the uuid of partitions.

Looks for the partition of block devices found in /sys/block/<device>/<device>*
Then looks for the a link to the partition device in /dev/disk/by-uuid.  The link name is the UUID.

JIRA: FACT-234
(maint) Remove trailing spaces in blockdevices_spec
Merge branch 'feature/facter-2/patition_uuid_fact' into facter-2

* feature/facter-2/patition_uuid_fact:
  (maint) Remove trailing spaces in blockdevices_spec
  (FACT-234) Add blockdevice uuid fact
Merge branch 'facter-2'

* facter-2:
  (maint) Remove trailing spaces in blockdevices_spec
  (FACT-234) Add blockdevice uuid fact

Conflicts:
	lib/facter/blockdevices.rb
	spec/unit/blockdevices_spec.rb