Fixing iOS build
Merge pull request #366 from stopiccot/ios_fixes

Fixing iOS build
WIP on error reporting system

- add error reporting callback to Vtr::Level::validateTopology
- switch printfs to callback
- add error code enums to Vtr::Level
- route Far::TopologyRefinerFactory::reportInvalidTopology through Vtr::Level callback

note:
- Vtr::Level::validateTopology needs to check creaase tag indices
- topology validation should be client-code driver in TopologyRefinerFactory (turned off in the code at the moment)
Remove Hbr compatibility from Sdc::Options

full backward compatibility is assumed to not be possible any-more
Fixing ProtoStencil mem leak
fixed code style of stencil leak fix
Merge pull request #367 from hsdk/dev

Fixing ProtoStencil mem leak
Removing non-manifold options : the feature is not ready yet for Beta evaluation
Enabled the "triangle smoothing" option for Catmark edge vertices.
Fix smooth triangles catmark weights

- rename enums in sdc/options
- add support for "smoothtriangles" tag in Shapes
- add 2 test shapes to glViewer
Fix error string conversion to use swtich statement (safer)
Fix tutorial include paths

- now prettier with <opensubdiv> prefix
Rename Sdc::Options vertex boundary interpolation rule enums

- VVarBoundaryInterpolation is now VtxBoundaryInterpolation
- enum prefix change from VVAR to VTX
- generel cleanup / doxyfication
- update of beta / release notes
Rename some members of Far::TopologyRefinerFactory::TopologyDescriptor for consistency

- propagate changes to tutorials / examples
Refactor Vtr::Array for better "const" safety

Const' declared instances of Vtr::Array do not protect the pointer held
privately by the class properly. In order to force the compiler to
protect this pointer, we removed all non-const accessors from Vtr::Array
(now renamed Vtr::ConstArray) and moved them to a child class (Vtr::Array),
which requires const_cast<> operators internally to allow access.

The change & renaming is then propagated to all internal dependencies.
Fix Windows build