feat: Add parameter to allow error printing suppression

[waltner]

Allow for _send to fail silently without printing the error message. Often it is useful to handle (and print) the error outside the _send function. This commit adds a print_err argument (defaults to True), so to suppress the error printing one can simply set this to False.

This should be especially useful if more sophisticated error handling and logging is implemented to customize the errors without having prints that are neither formatted nor have any debug level associated to it.

[waltner]

Just saw that there are some PRs that go into the same direction (#16, #19) so there is need for such a solution. I would propose to user logging (+ use of log levels) as in #19, as it is part of the Python standard library.