grades saving done!
Teacher View: saving and reading Grades
Revert "Teacher View: saving and reading Grades"

This reverts commit b9ad59a9bff099cfb00728d088c188b29c982d43.
Merge branch 'master' of https://github.com/mdipierro/lms299
Teacher View: saving and reading Grades
Update student view.
Update student grading view.
Teacher View: calculates computed Grade
added columns: computed grade, final grade and comment ( not saving to database yet).
added validation for hw grades ( number only).
Teacher View: color added for computed grade that is less then 70 ( red) and less then 80 ( yellow).
Merge pull request #65 from matus85/master

Teacher View: saving and reading the grades for all students