Merge pull request #268 from Genshin/fix_simple_grades

Fix simple grades
[frontend] Fix students index search pagination
[frontend] Prefill students form fields with js from params[q]
Merge branch 'master' of github.com:Genshin/GAKUEngine
[frontend] Fix external_school_records/new fields
[frontend] Add edit to students/external_school_records
Merge remote-tracking branch 'origin/master' into revise_student_views
fixed header nav & css