Merge pull request #65 from objcow/master

Resolved issue #12 (It would be nice if links added by users can be opened in a new tab in the browser )
Merge pull request #66 from objcow/master

Resolved issue #32 and prettified the exercise page
Fix solution editing

Fixes #57, Error Editing an Solution - Thinks it is a Problem
Use s3 for file uploads.

Fixes #58.
Update author info

Fixes #55.
Add missing template file.

Related to #55.
Merge pull request #84 from objcow/master

Resolved issue #82 and reverted change to db config
txt download option added

Also fixes #68 which is related.
Merge pull request #92 from objcow/master

For issue #85
remove line in pdf; add "remove from cart"; autorefresh after clear cart
Merge pull request #94 from yingmao/master

hide cart when not logged in
resolved issue #114