Add python type annotations to some older python files

[johnwlambert]

• Add type hints per PEP 484 (https://google.github.io/styleguide/pyguide.html#221-type-annotated-code). Some were previous added as part of docstring. These cannot be used for static analysis, so moved to function signature itself.
• remove dangerous wildcard imports
• fix some erroneous docstrings
• add some keyword args for readability

Files affected:

• test_Pose3SLAMExample.py
• circlePose3.py
• plot.py
• visual_data_generator.py

[ProfFan]

It appears that the Python unit tests are failing, but otherwise looks good :)

[johnwlambert]

It appears that the Python unit tests are failing, but otherwise looks good :)

thanks @ProfFan, should be fixed now

[ProfFan]

Noice!

[varunagrawal]

There's a missing import for Pose3 that was introduced in this PR. We really need to add more Python tests.

[varunagrawal]

Also, @johnwlambert what formatter are you using? We all use yapf in case you use something else.