Color/text information takes too much space in src_browser

[kamahen]

trafficstars

The colorization information is in a very naïve format that takes up a lot of space when loaded into the src_browser. It should instead be stripped out and put in external files, and transmitted to the src_browser front-end as needed.

This also applies to the /kythe/text facts.

[kamahen]

Consider using BerkeleyDB. More discussion here: https://swi-prolog.discourse.group/t/scaling-to-billions-of-facts/380/9