Provide Command class to hold commands. Add helper for creating arrays of create and delete commands.
Use Command instances for commands. Add commands via helper methods
Trim whitespace when creating commands
Error and bail out unless command allows failure
Merge branch 'extra-node-commands' into combo-features

Conflicts:
	lib/spiceweasel/execute.rb
Provide requires to load properly
Merge branch 'extra-node-commands' into combo-features
Allow failure by default to keep current behavior consistent
Merge branch 'extra-node-commands' into combo-features
Add command helper support to berksfile
Keep array initialization
Merge branch 'extra-node-commands' into combo-features