Added DisplayStep?.php, a visual representation of a contained Step (Questionnaire/Dashboard?/etc..) object in a pipeline. Allows icon-based presentation of pipeline.
Fixed StyleSheet?.php class, can be passed string argument (style name) to choose different .css files.
Added Logo class, basically the same as classes_old/Logo.php
Added placeholder icons and some UI elemtent images for use in pipelineEditor.php
