Adapted to Magnum changes.
Game: define AbstractHudText destructor in source file.

Was causing undefined deletions (definition of Text::GlyphCache not
present on destruction).
Updated Find*.cmake modules.
Renamed NaCl-specific files to hint that they belong to NaCl.

WebApplication.css, however, is not NaCl-specific.
Updated toolchains submodule.
Initial Emscripten port.

At least splash is displayed, but some resources can't be found (don't
know why).