Add camel case API

[2bndy5]

This adds all the API from the old individual python wrappers. The goal here is make the old examples portable by changing only the import statements. So far, I've tested this lib using a python example from RF24/examples_linux (getting_started.py), and it works wonderfully.

Just to reiterate, the old py examples from the individual wrappers can be updated by simply changing

from RF24 import RF24, RF24_PA_LOW
from RF24Network import RF24Network, RF24NetworkHeader

to

from pyrf24 import (
    RF24,
    RF24_PA_LOW,
    RF24Network,
    RF24NetworkHeader,
)

[2bndy5]

This is well tested now.

Going forward I'd like to make this package the recommended replacement of RF24* python wrappers because it doesn't require users to build and install the C++ libs (its all contained within the python env).