fix unicode issues.
reduce fontsize
add flask-script and gunicorn to the dependencies
add support for user accounts and login/logout
restructure the whole app back into one file
add fenced_code extensions

This markdown extension support code block with tilde (```) syntax like github
Merge pull request #1 from lowstz/patch-1

add fenced_code extensions
Update requirements.txt

miss Flask-Login==0.1.3
Merge pull request #4 from lowstz/patch-2

Update requirements.txt