Scientific notation on y axis appears when unhelpful

TensorBoard plots switch to scientific notation for 5 digit numbers, which requires more characters to represent, and actually hides relevant precision, as demonstrated in the attached screenshot.

-1.329e+4 -- 9 characters for 4 digits of precision and sign.
-13290 -- 6 characters for 5 digits of precision and sign.

It seems clear that scientific notation should only be enabled when the range of the plots contains numbers with more digits than would be used with the (less precise) scientific notation representation. In other words, scientific notation should only be used when one or both ends of the range has a magnitude >= 10^(5+desired digits of precision), where the 5 comes from the first digit, the decimal point, and the minimum number of exponent characters, which is 3.

The same basic reasoning also applies to numbers close to 0.

• TensorBoard version (from pip package, also printed out when running tensorboard)
  TensorBoard 67
• Python version (e.g. 2.7, 3.5)
  Python 2.7

Start by locating the TensorBoard plot axis-formatting entry point and reproduce the y-axis behavior described in the issue, using the attached screenshot and numeric examples as reference. The work is done when scientific notation is used only when it represents the plotted range more compactly without hiding relevant precision, including for values close to zero.