[Add] support for auto-concatenation and Fix multiple adaptToBackend() issues

Added support for auto-concatenation: the Concat operator is replaced by direct allocation when possible during scheduling.

Fix multiple adaptToBackend() issues.

Detailed modifications

• Add expandMetaOp() recipe to expand a single MetaOperator node;
• Add sorting option to getStaticScheduling() that includes AsSoonAsPossible and AsLateAsPossible;
• Add generateMemoryAutoConcat() that handles auto-concatenation directly in memory, with the following changes vs N2D2:
  • Support both NHWC and NCHW formats;
  • The memory layout for Concat is still generated.
• Add missing binding for a constructor of ImplSpec::IOSpec;
• Fix bugs in OperatorImpl::getAdaptation():
  • Backend was not set, set it to be the same as the adapted node;
  • Fix confusion between IOSpec and requiredIOSpec;
  • Return the node instead of a meta-op if no adaptation is required.
• Fix issue in Transpose_Op to allow a permutation vector larger than the input vector;
• Changed adaptToBackend() behavior to not introduced meta-ops.