Switchable Analytics fix (final, I hope)

[rdavydov]

Description

enable_analytics option in twitch_minerfile toggles Analytics needed for the analytics() method

Disabling Analytics significantly reduces memory consumption and saves some disk space by not creating and writing /analytics/*.json.

Set this option to True if you need Analytics. Otherwise set this option to False (default value).

See example.py. If no such option - defaults to False.

Fixes #2, #10

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

From tests that I've done on my Windows 10 PC - it reduces memory consumption significantly - from 800 MB with analytics enabled to 40 MB with disabled. On my Linux boxes it also becomes less memory-hungry.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (README.md)
• My changes generate no new warnings
• Any dependent changes have been updated in requirements.txt