add an applet to b2d init; b2d start; export DOCKER_HOST=tcp://localhost...

[SvenDowideit]

...:4243

this may well simplify things for the new user -

• run installer
• open Applications
• click Boot2Docker Start icon

leaving them with a running b2d vm, and in a terminal session with DOCKER_HOST already set.

ie - as simple as the Windows experience.

(I will add some more hints to it later - need a haircut :) )

[SvenDowideit]

this will help #13 - but I need to figure out something for upgrading too.