[dmd-internals] generating pull requests for DMD

[Walter Bright]

For those doing compiler patches, I know it's a tough job, and thanks!

But please consider running the dmd test suite (and try to build/run phobos 
unittests) before issuing a pull request. There are a lot of interdependencies 
in the compiler, and the test suite is designed to flush them out. The cool 
thing is the test suite consists of cases that are already minimized! The suite 
also is designed to not take that long to run.

I run it constantly when I do dev on the compiler, and I constantly get dinged 
by it for something I overlooked. I consider the D test suite to be a major 
asset for us.

Please use it. If you've got problems using it, please post here and we'll try 
to help.