Fix formatting to bind column labels at render time

[papajohn]

[x] Wrote test for feature
[x] Bumped version number (delete if unneeded)

Changes proposed:
Change formatter so that the label length is observed when the table is rendered (in case it changes).

Fixes #272

[coveralls]

Coverage increased (+1.07%) to 75.832% when pulling c43cf2c on join into 5381643 on master.

[coveralls]

Coverage increased (+1.07%) to 75.832% when pulling c230f2e on join into 5381643 on master.