Move consts related to user settings to class level.

[caternuson]

The register addresses are OK at the module level. But for things like mode (maybe that's the only one?) there is no convenient way to access them when using the recommended code setup:

import board, busio
import adafruit_ads1x15.ads1015 as ADS
from adafruit_ads1x15.analog_in import AnalogIn

i2c = busio.I2C(board.SCL, board.SDA)
ads = ADS.ADS1015(i2c)
ads.mode = 0 # don't have access to _ADS1X15_CONFIG_MODE_CONTINUOUS  

Having these at the class level would allow:

ads.mode = ADS._ADS1X15_CONFIG_MODE_CONTINUOUS

May also want to change their names? Or just add new ones? So could:

ads.mode = ADS.CONTINUOUS

[tannewt]

Module level is how I've seen it done in other places. The more proper way is to do it as a Python enum which is essentially an empty class with statics. So it'd be ads.mode = ADS.Mode.CONTINUOUS. digitalio.Pull is modeled this way.

[caternuson]

Thanks. That make more sense. I'll try and implement something and PR it.

[sommersoft]

Just tossing in my support/agreeance @caternuson. These could definitely be more useful at the class level, especially so that the user doesn't have to remember which integer matches a mode.

[caternuson]

Yah, I totally did a sloppy job on this. I hit this myself when I was trying to help someone change mode and realized they didn't have anything convenient to use on the right hand side. They need to be able to do ads.mode = SOMETHING_OBVIOUS_AND_EASY_TO_REMEMBER

[caternuson]

Done. See #25

[makermelissa]

Did you want to do the release?

[makermelissa]

Or I can... :)

[caternuson]

Thanks!