Add note about using release profile to create bin

I don't know too much about Java or Maven, and it took me a while to figure out how to create the binaries that are precompiled and included in the zip download. It's probably second nature for y'all, but this line would've saved me a few hours of headache. What do y'all think?
Merge pull request #89 from gempesaw/patch-1

Add note about using release profile to create bin