Make things tunable via kwargs

[caternuson]

For #19 and as another option to #20 and #21. This approach uses kwargs instead of properties.

This will allow for "tuning" of the underlying timings for better support of other flavor addressable RGBs. There are four parameters (new kwargs) that are involved:

• frequency - The SPI bus frequency, really only two values that matter. Added as an init parameter.
• reset_time - The reset time value (TRST). Added as a new property.
• bit0 - The byte that defines timing for a 0 bit (T0H+T0L). Added as a new property.
• bit1 -The byte that defines timing for a 1 bit (T1H+T1L). Added as a new property.

This example shows tweaking the bit 1 pattern which may work for the case discussed in #19 and #20:

$ python3
Python 3.6.9 (default, Jul 17 2020, 12:50:27) 
[GCC 8.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import board
>>> import neopixel_spi as neopixel
>>> pixels = neopixel.NeoPixel_SPI(board.SPI(), 1, pixel_order=neopixel.RGB, bit1=0b11111000)
>>> pixels.fill(0xADAF00)
>>> 

[caternuson]

@geekmomprojects Can you test this PR's approach as well? No reason why it shouldn't work since it's just a different approach for setting things up.

[tannewt]

Looks good to me! Thank you!

[geekmomprojects]

Late to the party, but it works great for me. Thank you!