[DOC] Doc comment for Page / SiteUrl ViewHelper
[DOC] Doc comment for Page / Menu ViewHelper
[TASK] Check if $files is array in clearCacheCommand() of AssetViewHelper
[DOC] Update copyright year, Iterator / Values ViewHelper
[TASK] Remove unused attributes "start" and "length" from Iterator / Values ViewHelper
[FEATURE] Form / HasValidator ViewHelper (Condition)
[TASK] Use Form / HasValidator ViewHelper as parent of Form / Required ViewHelper

The "Required" ViewHelper is simply a check for HasValidator using NotEmpty as validator name. Every checking capability is contained in HasValidator.
[TASK] CGL cleanup, Random / Number ViewHelper
[TASK] Enable respect for "as" attribute in Iterator / Shift ViewHelper
[TASK] CGL cleanup and slight refactor, Iterator / Merge ViewHelper
[TASK] Refactor menu base class in preparation for new VHs
[TASK] Fix indentation
[TASK] Fix usage of obsolete method
[FEATURE] Add list menu VH as discussed in #44
[BUGFIX] Fix method argument and typo blocking rendering of deeper levels
[DOC] Doc comments in Menu ViewHelpers' initializeArguments methods
[FEATURE] Add directory menu VH as discussed in #44
[TASK] Increase source readability
[BUGFIX] Move Asset's contentPostProc hook slightly upwards in stack

This allows the Assets to function in the case of a cached context combined with no user being logged in when page is being cached.
[TASK] Fix indentation