add permissions
Merge branch 'master' of github.com:Pylons/substanced
add the possibility of setting a callable as a condition for enabling or disabling buttons
add tests for conditional buttons
update narrative docs
Merge pull request #29 from Pylons/feature.conditionalbuttons

Feature.conditionalbuttons
allow form element translations
Merge branch 'master' of git://github.com/Pylons/substanced