Add links for facts and nodes in fact table macro

Added links to the node page from the facts_table if show_nodes is True.
Added links to the facts page from the facts_table if show_nodes is
False.
Added logic to switch TH table from facts to nodes if show_nodes is True.
Merge pull request #19 from daniellawrence/fact_table_template_title_and_links

Add links for facts and nodes in fact table macro