merge changes from ITXT-4
add missing files from ITXT-4
Merge final changes
some code-level documentation
Merge pull request #8 from crowbar/release/pebbles/master

pull changes from dell
Merge pull request #9 from MirantisDellCrowbar/release/pebbles/master

pull changes from dell
refactoring feature of validating chef attributes
tiny fix
raise error when node not ready -> rescue to sleep(1)
typo
add missing ';'
typo
add empty lines
Merge pull request #563 from MirantisDellCrowbar/feature/ITXT-29/pebbles/master

Reboot and "filter node by attribute" features required for Intel TXT