Better show methods for triangle faces

[asinghvi17]

Currently, the offset integers are shown using octal notation. Could we convert to decimal instead?

 TriangleFace(OffsetInteger{-1,UInt32}(0x0000003c), OffsetInteger{-1,UInt32}(0x0000003b), OffsetInteger{-1,UInt32}(0x0000003a))

could be be

 TriangleFace(OffsetInteger{-1,UInt32}(60), OffsetInteger{-1,UInt32}(59), OffsetInteger{-1,UInt32}(58))

or something.

[ffreyer]

They have been improved in 0.5 (to use GLIndex where applicable and print UInts as ints)