Performs range checking on the inputs to Mesh::Mesh() before allocating
the storage array.
Bug: 20674682
Change-Id: I4fc918a8c312d967dd6d9f91a098b2e0a7081027
the Mesh object can be part of each Layer (at least currently).
also reworked the Mesh code a bit to make it easier to access
the vertex data.
Change-Id: I0490851ba898f0aa2e55b62958dcd8bdb535e98b