Fix url provider

Hello Mr. McSpadden,
I was updating my slightly modified version of your MinecraftEdu recipe and discovered that it was not able to grab the devel builds. Looking more closely at the MinecraftEduURLProvider.py, I noticed that since it was converting the version number to a float, the recently released 1.710 was getting converted to 1.71, and thus the returned URL was incorrect and failed.

This is kind of a quick and dirty way to solve it. Feel free to ignore and do it the way you like it ;).