Extending file-reading capabilities and some minor code changes.

Changes:
- fetching a moodle file item per logged in user
- Page icon changed
- Migration1 fixed

Known Issues:
- undeterministic sorting order of sections in a course
- currently any users security_token can be read out dm4
- missing existence Check for "Web Resources" and "Moodle Files"

Documentation:
Currently depends on the necessary capabilitues set, the most basic features activated (REST/JSON) i
and the following functions assigned to a new custo web service:
- 'core_webservice_get_site_info()'
- 'core_enrol_get_users_courses()'
- 'core_course_get_contents()'