TODO

nddiff
    --ctx-path <path>
    --ofmt html

ndproc
    --disable-rule <comma,separated,numbers,list>
    PATH DEFINITION to all mods docs
    'optional' opt to mods opts %)
    validate_rules method for all modules
    'include' rule directive (replace rule by external rules, recursively)

App::NDTools::NDProc::Module
    complete rule using defaults if not all vital opts provided
    also - non default opts only when dump rules

App::NDTools::NDProc::Module::Merge
    --match <path> # (combined with path) -- to implement fair pairwise merge (filter like "defined" used)
    make per-merge path opt to be able as list

App::NDTools::NDProc::Module::ListSort
    --path <path> --by <subpath> --numeric --decs

App::NDTools::NDProc::Module::Patch
    ndpatch should be as a wrapper for it?