dget - getting code from github

[Walter Bright]

Currently, getting D code from github is a multistep process, that isn't always 
obvious. I propose the creation of a dget program, which will:

     dget https://github.com/D-Programming-Deimos/libevent

download the libevent code and install it in a subdirectory named libevent. Of 
course, the url could also be:

     dget github.com/D-Programming-Deimos/libevent

since https is assumed, or:

     dget D-Programming-Deimos/libevent

since github is assumed. And since Deimos is a known library,

     dget libevent

can also be hardwired into dget.

Anyone want to implement such? It ought to be fairly straightforward, and will 
be a nice timesaver for a lot of people.