Add dependency to Django >= 1.2

[adamn]

easy-thumbnails, as an emerging library, should require Django 1.2+ and should be explicit about it in the setup.py file.

[SmileyChris]

I don't see why it needs to be explicit unless there's a requirement. Which there might be, I can't think if it is right now though... I don't mind it not being explicit unless this is the case.

[adamn]

It should at least require django generally, most of the packages are moving in that direction.

[SmileyChris]

Yeah, I guess so. I just seems a bit odd that you'd need to bother putting the dependency for the framework in your application. I'll ask around djangocon to get some opinions :)

[SmileyChris]

I'm not going to bother with this for now. No consensus that this is a good idea.