Make PasHi silent when run without errors or warnings

[delphidabbler]

For v3 I'm proposing to adopt the Linux convention of programs emitting no output when they execute without errors, other than any output sent to stdout when required.

Therefore PasHi should not emit its sign on message by default.

Output should only be sent to stderr in case of errors or warnings.

[delphidabbler]

This change would be that the current verbosity default level will have to change, which us why implementation must wait for v3.

So, once this issue is accepted, the --verbosity command documentation needs to be updated to flag the current default (normal) as deprecated.

The new v3 default will be a verbosity state not currently supported in v2, unless issue #15 is implemented. In this case the default verbosity state will change from info,warnings,errors (= normal) to warnings,errors.