Update the filter
Update the local/mediacore libs.

* Update for LTI
* Refactor classes
* Delete locallib
* Update settings page
* Rename settings constant
* Add new upgrade script to remove old config db data from v1.6
Add new filepicker/repository
Move tinymce plugin to v2.4 dir
Add .editorconfig to unify formatting
Update tinymce plugin to use new local/lib classes
Add bindfs helpers
Update filter, local/mediacore, repository and tinymce plugin versions
Update install instructions in README.md
Delete old screenshot
Merge branch 'new-chooser'
Make README syntax more concise
Urlencode context params
Clarify/Standardize some wording in README.
Update compatible moodle versions in README.
Bold some things in the readme for readability.
Make signing happen on chooser/ and chooser/ieframe_proxy endpoints and not chooser_js_url