core/transformatiuon: renamed KernelArgument to KernelParameter (to avoid confusion with computation.KernelArgument)
core/transformation: fixed phrasing in Transformation docstring
doc/api/core: explicitly specified exported classes
core/computation: some documentation and cosmetic changes
core/transformation: added some debug info to KernelParameter.__repr__
core/signature: added Annotation.can_be_argument_for()
core/computation: cleaned up, fixed algorithm to handle repeating arguments properly
core/signature: more descriptive error message