MDL-44616 behat: Adding steps to test MDLQA-1709 and MDLQA-62

- In an assignment with file submissions enabled,
  students can upload a set number of files.
- In assignments with file uploading enabled
  the Student can use File Picker to upload files.
MDL-45132 curl: Unit Tests for file uploads
MDL-45116: Workshop submission title displays behind author picture
Merge branch 'MDL-45132-26' of git://github.com/FMCorz/moodle into MOODLE_26_STABLE
Merge branch 'wip-MDL-45116-MOODLE_26_STABLE' of https://github.com/kwiliarty/moodle into MOODLE_26_STABLE
Merge branch 'MDL-44616_26' of git://github.com/dmonllao/moodle into MOODLE_26_STABLE
MDL-45119 ajax: AJAX exceptions need a String in the Link
MDL-45119 ajax: Correct use of COUNT in exception dialogue
MDL-45119 editpdf: Do not load quick comments in read-only mode