Fixed broken image serving in development server

[crohkohl]

Separation of changes in separate pull request: #199

On my machine the image serving, e.g. of the mean.jpg does not work.
The browser (tested IE and Chrome) cannot interpret the image probably due to the missing content type. The send_file function takes care of that all.

[lukeyeager]

Thanks for the fix! Looks like I was working too hard.

Can we go ahead and use send_from_directory while we're at it? Then we wouldn't need any of the checks for path manipulation.
http://flask.pocoo.org/docs/0.10/api/#flask.send_from_directory

Also, watch your extra whitespace on line 246.

[crohkohl]

send_from_directory sounds even better! Will you change that or should I do it?
I am still getting used to that white-space thin in python. All me editors use tabs ... I will need to adjust them.

[lukeyeager]

I can't push commits to your fix_file_serving branch - you'll have to do that. FWIW, it seems to be this simple:

jobs_dir = config_value('jobs_dir')
return flask.send_from_directory(jobs_dir, path)

[crohkohl]

okay, I put in your suggested change and squashed the two commits

[lukeyeager]

I fixed the docs merged this into master with 63a8456.

Thanks for the contribution!

[crohkohl]

great!