Bump dev version to 11.8.0.alpha.0

Ongoing bugfixes for 11.6.0 release will occur in the 11-stable branch.
shell_out to diff => diff-lcs, cleaned up tests, updated gem versions
required diff libraries
[CHEF-4380] Fix missing include on shellout mixin
Added license information
IO:: -> IO.
Merge pull request #899 from juliandunn/CHEF-4380

[CHEF-4380] Fix missing include on shellout mixin
changed Ohai -> Chef in NOTICE
Merge pull request #898 from opscode/OC-8693

OC-8693