Information aboutreleases of mingw-w64

To understand the way mingw-w64 did in the past for 1.0 branch the releasing, needs some description. At the beginning we were using rolling-release mechanism. Which means that we didn't branched/tagged for new releases. This meant that each snapshot itself was an new release. This approach has proven to be not usable and accepted by most of our users. So we created the 1.0 version branch, but still there were no specific version tags used on this branch. Means the 1.0 branch was still a rolling release.

As this approach has still shown the same problems to our users as initial approach, we decided now to use branches for major versions and tag explicit a version as release. Those tags can be found in our svn-repository as usual under /tags/ tree.