Enable link alert and exercise sorting on tabular coach report view

Problem: Issue #288

Behaviour: Clicking 'link' option on tabular coach report gives Javascript error and nothing else.

Fix: Report current window link when clicking this button when dynatree is not loaded for topic selection - i.e. tabular coach report.

Problem: Issue #222 

Behaviour: Exercise headings in coach report were not in order.

Fix: Sort Exercises by position in sub-topic map before returning to context.