Various issues

[gijzelaerr]

This:

• introduces the parameter type and use this everywhere
• fix spelling mistakes
• fix examples as far as possible example/boolean.py and example/read_multi.py broken #271
• internal cleanup and restructure
• enable disabled tests
• Replace OrderedDict with the built-in dict #520
• Improve doc for area_read in client #493
• Make logo class look more like client class Merge logo code in client? #277
• rename snap7.typing to snap7.type to avoid naming conflict with typing module