Twiddly bits of small integer math

Had some issues making getItems() and indexOf() come out
correctly. This seems right.
Test getting a sub-section of the stream
Remove logging code
Stuff from debugging

Documented the data structure at the beginning of the file. You're
welcome, future self.

Made the screwball getMore() function always end with two results;
easier to know what to reverse.

Corrected an error in newSegment().