Update maximum for D&D system to 3.1.0

[paercebal]

While there might be translations missing, users upgrading to DnD 3.0.0 are surprised to find the whole module is out.

The original code set the maximum to "3", which should be equivalent to "3.0.0", but for some reason, isn't, so I guess this is ok to support "3.0.0"

I propose to let the maximum to be 3.1.0, because I guess there might be surprise patches to DnD3.0.0 (like, 3.0.1, 3.0.2) cause by minor bugs that escaped delivery.

[paercebal]

To clarify, re-enabling the module despite the potential missing translations, does have immense value to French users.

Indeed, without it, French users suddenly find they must either go back in version (and this is where not being a programmer puts you in a dire spot), or continue in English.

I had to help a friend who had this very problem, and I believe others are not so lucky to have a programmer friend with some bit of experience in the platform.

[paercebal]

Should fix issue: #38