Adding check for request.POST (django >=1.9) cf. request.REQUEST (django <= 1.8)

[jamonation]

Here's a little conditional that will handle older django versions and recent 1.9 and newer when calling preview on a markdown field.

[jamonation]

Hey @klen or @yavorskiy - do you need anything else to get this merged into master? I made sure travis will build, and this is working for those of using Django 1.9.x.

For reference, it looks like coverage 4.x doesn't need the [report] section for django_mardown given the size of the project, since it will report on anything in [run] by default. So I removed that section and everything looks good.

Would either of you mind reviewing this PR?

Cheers!

[iLikeKoffee]

@jamonation Awesome fix! Hope that will be merged! Thank you!

[jgruhl]

@klen are you still able to support this? I'd be willing to support at least the PR's that address the django 1.9 updates.

[ajoyoommen]

This PR needs to be merged.