Merge pull request #50 from aglos/Ohad's-branch

Ohad's branch
Merge pull request #51 from aglos/Ohad's-branch

in checker page:
Merge pull request #54 from aglos/Ohad's-branch

Ohad's branch
Merge pull request #58 from aglos/Ohad's-branch

Ohad's branch
Update README.md
Update README.md
Update README.md
Merge pull request #59 from aglos/Ohad's-branch

remove double ajax requests in grades.jsp
Merge pull request #60 from aglos/Ohad's-branch

fix in grades.jsp the page description
Merge pull request #61 from aglos/Ohad's-branch

separate jQuery part of grades from html file
Merge pull request #65 from aglos/Ohad's-branch

Ohad's branch
add a Admin user 
id: 201581436
password: hahaha
set the administrator Html
seting the Admin main page
add validity check for most of the admin pages
Merge pull request #66 from aglos/Ohad's-branch

commit
Merge pull request #67 from aglos/avshalom

Avshalom
updated static db: students and execrise.
add new future: lecture to add new execrise.
Fixed classes: Course, Execrise
fix wrong usage of classes
create exec.
Merge pull request #69 from aglos/sharon2

Sharon2