Make sure path special characteres are handled

[adiroiban]

See the list from here https://stackoverflow.com/a/31976060/539264

We need special tests for each os.. .for example handle : on macos or CON in Winddows

As compat we will have unit-test , but add helper to allow high level functional tests

Update mk.filename() as follow:

• Create mk.unixFilename mk.macFilename mk.WinFilename that will produce files that are always valid for that ok
• mk.filename will be automatically assigned to on of the above based on the current OS
• each mk.OSFilename will return names with valid printable Unicode
• each mk.OSFilename will return names with random values from each class ASCII, Latin, Special-Chars, Asian, Farsi ...etc

See if we can use https://hypothesis.readthedocs.io/en/latest/data.html