Information Collection improvements

*Title: Information Collection improvements

*Documentation:

Added the function 'data_map' for information collections which will
return attributes indexed by their identifiers. This provides another
method for templates to refer to attributes of an information collection.

For example:

{$collection.data_map.email}

Added the functions 'content' and 'hasContent' for information
collection attributes. These functions conform to the same interface as
contentobject attributes.

For example:

{if $collection.data_map.name.has_content}
Recorded name is: {$collection.data_map.name.content|wash(xhtml)}
{/if}

*Authors: Paul Forsyth ([email protected]), Vittal Aithal ([email protected])