Feature request: an option for not defining the default environments

[ptoche]

As can be seen from my question here, I inadvertently attempted to redefine the solution environment and got an error for it. An immediate workaround was to use other words, such as solutions (with an s), hints, discussion, answer. But since I was not using the default exercise environment with its solution environment, it seemed like a shame to have that most venerable word wasted. So I'm wondering if it would be possible to have an option to not load the default environments, such that the keywords solution and related could be used for customized environments.

And before signing off, a big cheers for a wonderful package.

[cgnieder]

This seems like a valid request. I'll try to come up with a solution that doesn't break the current behaviour