Specification v0.40.0 release tag

- Some of the table data for the specification has been moved into an XML
  base document. In the specification build, we use the XML to generate
  asciidoc tables to be included into the specification document. The XML
  can be used in other projects to stay in sync with changes to the
  specification.
- Convolution weights are now noted as inputs for all profiles. Previously,
  they were attributes to the convolution functions for the Base Inference
  and Main Inference profiles. Implementations may choose to optimize the
  weights if they are known at compile time, but it is no longer required to
  be compliant.
- RESIZE scale is now defined as a ratio of integers. This allows the output
  dimensions to be derived from the input dimensions without rounding.
- Remove rank limits on RESCALE and POW. This brings them in line with other
  similar operations in the specification.
- Inverted the definition of out_pad for TRANSPOSE_CONV2D. We have inverted
  the sign of the output pad values such that increasing out_pad values
  leads to increasing pad. This change also specifies a pad limit range of
  output pad values that give an output dependent on the whole input.