Do not crash if /proc is not mounted

When proc is not mounted pthread_getattr_np fails, so default
to 1MB stack in getStackLimit and to exactGC in MemoryManager

Change-Id: Ic7515fd420f2d39a656808d24a3915a657722891
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Fix some compiler warnings in tests and examples.

Change-Id: Ia739c995005635caf6fd0bd4e495ed8567350e83
Reviewed-by: Alan Alpert (Personal) <416365416c@gmail.com>
Add support for a separate index buffer

The renderer binds same buffer both for vertex and index data.
This is allowed on desktop & ES but is forbidden in WebGL.
Add a compile-time flag to disable this optimization(?) and
force using a separate buffer for the index data.

Change-Id: I57c17c883a55e02513a8e4427efb202cafaaf37e
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>