New qmake approach

This should allow us to have much better integration by generating the necessary gyp
files directly from qmake.
Mostly works for now, though we will most likely need to build the gyp generation
as we go.

  * Out dir logic is still crap and needs to be (re)worked.
  * In the same vein, we probably don't want the generated gyp
  content ending up in the source tree in the long run, which could prove tricky
  with relative paths to sources and all.