The WebGL build invokes cmgen for samples, which takes several minutes
in debug configuration. Let's use a release build for the host tools,
regardless of the build configuration for the target architecture.
* Try to clean up asset folders for sample apps.
This removes the build step where we copy a subset of assets, and makes
it so that FilamentApp hands out a "root path" for assets. For now this
is determined based on the location of the executable. This allows
developers to launch samples from any CWD.
Closes#11
* Restore asset copy to build.
Philip Rideout
Romain Guy