Fixes#79. Uses Download-File function from d654a53ec43038c42344f9cdbe0abc5b8ff9b387
Create appveyor.yml
Should send build notifications to gitter as well.
Adds appveyor build status badge.
Always compile launcher for AppVeyor
This is to catch any errors that may be caused by changes to the launcher or any outside scripts.
Up to now, init.bat would be overwritten when a user updated
Cmder. The new mechanism will create a new (mostly empty) file
for the user to enter commands which will then be executed on
each following startup.
