Merge pull request #23 from jbudynk/master

Fix #21. Add Iris's NED SED Service query type. Remove unused figure.
Merge pull request #27 from jbudynk/master

Fix #24. Moves Use Case and Custom Models to before Iris Stack.
Fix #29. Adds \url{} commands for URLs.
Fix #15. Add introduction to Iris built-in functions. Removes subsection 'Data Management' title from SED Builder section.