Normalize `value` in TrustAtom

[Harlan T Wood]

Feature:

link tag when complete looks like:

Ŧ→sushi[0x00].900000000[0x00]892412523[0x00]uhCEk…UFnFF
Ŧ→sushi[0x00]-.900000000[0x00]892412523[0x00]uhCEk…UFnFF

This feature is to normalize the rating part eg:

.900000000

AC:

• no leading zero
• always nine digits after decimal place
• negatives start with -
• max is .999999999 (never 1.0)
• min is -.999999999 (never -1.0)
• tests

Examples:

• passing in 0.9 yields .900000000
• passing in 1.0 yields .999999999

Impl:

• values come in as strings
• "zero pad" the input number
• special case: 1 -> .999999999, -1 -> -.999999999