Removed non-api prints from old_api test
Added ndim property to SignalView
Fix: added shape and elemstrides properties for Constant
Added signals for alpha and weights

Encoder, Decoder, Transform and Filter coefficients have shapes, can
potentially change over time (plasticity / adaptation / learning), and
are indexed the same way as other signals in the OpenCL codebase.  This
change standardizes the handling of numbers within the simulator by
making all these constants into signals.
Simulator overide for CircularConv TestCase