Fix broken span test.

close #3
Some doc updates to make golint happier.
Getting rid of .travis.yml
Increased coverage of time formatter
Coverage -> 100%

Figured out how to induce a float parser error -- with empty input of
course.
Convert all the asserts to test tables
got and exp fields were swapped in testing
Don't allocate room for more commas than necessary

closes #4
Error on excessively large byte values
Big number byte sizes
Now happily formats exceedingly large sizes
Shove commas into big.Ints
Benchmark BigComma
Don't overflow counters on 32-bit systems

close #6
Fixed incorrect error message in failed test
Refactored common big stuff into big.go
Some lint fixes