MDL-36966 Assignment: Bug - Student submission appears graded by themselves.

Fix a bug when a student editing his submission after it has been graded, it changes the 'graded by' details to the student's name in the feeback summary
MDL-37037 assign Show message if no files to download
MDL-37037 Assignment Some minor refactoring of the previous patch

This just makes the control flow a bit easier to read.

I also added a continue button to take you back to the grading page.
MDL-36455 blocks: removed ability to add blocks to the My Moodle page that did not make sense in that context
MDL-37225 reset cachstore_static store when purging
MDL-35653 - mod/wiki: Force format now lets users edit wiki pages.

Thanks to Tõnis Tartes for part of this solution.

When force format was selected in the options, trying to view the
wiki would redirect to the front page with a message saying that
you do not have permission to edit this page. Students had no way
of viewing any entries or creating the first page.

When in force format it skips a page , which would be considered
uncessary for students, but this means that the group id is not set
and this is what is causing most of the problems.

I also have included a check to see if the title is default and whether
the user has permission to view all groups. In these situations the
intermediate page is displayed.
MDL-37015 Resource: link in onclick should not contain html special char
MDL-35833 - Blocks - Adding alt and title attributes to the docked-block panel close button
MDL-37263 cache: fixed event invalidation coding error
MDL-37233 do not show skype status icon on https sites

Funny that the same company that implemented the IE security warnings is unable to set up SSL on the Skype status server…
MDL-37283 import tinymce spellchecker 2.0.6.1
Merge branch 'MDL-36455_master' of git://github.com/markn86/moodle
Merge branch 'master_MDL-37225_static_cache_purge' of git://github.com/brki/moodle
Merge branch 'wip-MDL-35653-master' of git://github.com/abgreeve/moodle
Merge branch 'wip-mdl-37015' of git://github.com/rajeshtaneja/moodle
Merge branch 'MDL-36966-master' of git://github.com/damyon/moodle
Merge branch 'wip-MDL-35833-master' of git://github.com/phalacee/moodle
MDL-37290 course: fixed up navbar when editing categories
Merge branch 'w51_MDL-37283_m25_spell' of git://github.com/skodak/moodle
Merge branch 'wip-MDL-37290-m25' of git://github.com/samhemelryk/moodle