Small style fix for the menus
PaladioTheme::GetUri only resolve relative paths

Added detection for absolute and protocol relative uris in
PaladioTheme:GetUri
Added GetRootUris to get the roots available

GetRootUris returns the lists of roots used to resolve relative uris
PaladioTheme will accept lists separated by ";"

When requesting scripts or stylesheets, multiple items can be requested
by passing a semicolon separated string. This reduces the hassle when
using these from templates.
BuildAttributeString new allows to filter attrs.

When using BuildAttributeString it is now possible to pass the list of
desired attributes.
Improved ArraySkip and ArrayTake for mixed input

Both Utility::ArraySkip and Utility::ArrayTake will be able to handle
null and string as input for the $keys paramter in addition to being
able to handle arrays.
template.pet.php improved to use recent changes

- template.pet.php is now using PET_Utility::BuildAttributeString and
PET_Utility::InvokePET more effectively
- removed support for optional menu and changing menu position via
attributes
Added title.pet.php used in template
Small refactor for post.pet.php