Redirect /software/opencmiss/ removing trailing slash

Use statamic's vanity URL feature to redirect the redirection of opencmiss.org from /software/opencmiss/ to /software/opencmiss i.e. without the trailing slash as the new version of statamic shows a blank page for the former URL.
Change images on Cmgui pages
Fix errors and omissions in zinc axis viewer tutorial.
Merge pull request #56 from rchristie/master

Fix zinc axis viewer tutorial. Redirect opencmiss/