Allow to set default license for uploads

[spaetz]

On each upload via web interface I have to select the license per media. I have strong default preferences and would like to set my default preference in my profile settings. This one would be pre-selected when uploading via web.

Apps uploading via the API will likely select their own license or could then use the user default license if they don't specify one.

[Mark Holmquist]

Change submitted for review, bug paroneayea to get 'er merged :)

​https://gitorious.org/mediagoblin/mediagoblin/merge_requests/44

[spaetz]

Setting this to 0.3.3 so we target it for the next relase after 0.3.2. I'll assign this to me to review the change and merge it post-release.

Chris has declared feature freeze for 0.3.2 so I won't add it to master before our release.

[spaetz]

I just reviewed and rebased to current master. The result is in my branch 521_license_preference.
I only fixed one unicode issue, otherwise this is the patch by Mark.

[Christopher Allan Webber]

Great work! Thanks so much, Mark! (And thanks for the review/rebase spaetz!)

People have wanted this feature for ages, so I'm thrilled to have it in. :)