move some methods from Context to ModifyRuleCommand
create a getThemes command to improve startup performance
#886 getThemes command and load theme resources on demand
Upgrade to Zazl Version 0.5.1
#3238 Remove 4 segments if it is a review URL
#886 better error handling
Merge branch 'master' into getThemesCommand
Small code cleanup.
Fix exception when opening cascade by replaced a relative
require(relativeURL) with an absolute require(absoluteURL). @peller
Merge branch 'master' into 2444-MultiPageSketching