enhancement(decide/match): support multi-file risky based matching

[ShanaryS]

This mainly is to support multi-file risky based matching moving the 100% MATCH_PARTIAL matches to MATCH_SIZE_ONLY. I refactored decide.js to the state it will be downstream.

1st commit:

1. The priority of decisions
2. Reporting more granular decisions
3. Caching all snatched .torrent files and saving infoHash with decision if present (might as well start doing this now for cache-search-queries). We can optionally cleanup based on modified time since it is updated each time it's used.
4. Better error message for decisions and snatch.

2nd commit:

1. Support multi-file risky based matches

[mmgoodnow]

architecture looks good, I like the new organization of decide.ts. I have several comments but they're pretty minor for the most part

[mmgoodnow]

LGTM pending the resolution of these threads:

#689 (comment)
#689 (comment)

[ShanaryS]

Good to merge. Had to update humanReadable to use absolute values for Math.log.

[zakkarry]

Good to merge. Had to update humanReadable to use absolute values for Math.log.

#695 ?