MOD common error types

ADD IllegalArgument
MOD remove 'error' from textual rep.
MOD a more intuitive and simpler API and impl.

TODO implicit code from struct field name
TODO examples
TODO formal test
TEST ADHOC OK
MOD API use flags.MapStruct instead of MapStructPtr
ADD adhoc test / example usage
ADD errors.Timeout
ADD kriterium/component/process

ADD  component.go - for now just to load sub-package process
MOD  kriterium.go - includes componet

ADD  process package interface def & CnC impl.
TEST OK
FIX TEST use explicit go import
MOD add kriterium/component to the include all import list
MOD acceptable API for process command and control

MOD  substantial change to clarify api semantics
MOD  tests to check os signal handling
TEST OK