#14 updates

- short links will only be displayed on normal pages
- removed the body classes e.g. page-id-1 for virtual pages
- the correct rel_canonical update
Merge branch 'master' into #14-wp_shortlink-missing
#14 added unit tests
#14 added unit test for displaying the body class
Merge pull request #44 from deanearlbartolabac/#14-wp_shortlink-missing

This pull request fixes issues #14