Fix wrong line width calculation in max_width for colored text

[wkentaro]

issue: #146
related to: frostming/legit#168

[wkentaro]

Before

('git branches', 12)
git branches
(<YELLOW-string: 'git branches'>, 12)
git
branches

After

('git branches', 12)
git branches
(<YELLOW-string: 'git branches'>, 12)
git branches

[wkentaro]

Please review this and hope to be merged.

[wkentaro]

This is necessary to fix a display problem in https://github.com/kennethreitz/legit .

[wkentaro]

With this, the display of legit install fixed.

before

% legit install
The following git aliases have been installed:

  git                  !legit branches
  branches
  git graft            !legit graft
  git                  !legit harvest
  harvest
  git                  !legit publish
  publish
  git                  !legit unpublish
  unpublish
  git                  !legit sprout
  sprout
  git sync             !legit sync
  git                  !legit switch
  switch
  git                  !legit resync
  resync

After

% legit install
The following git aliases have been installed:

  git branches         !legit branches
  git graft            !legit graft
  git harvest          !legit harvest
  git publish          !legit publish
  git unpublish        !legit unpublish
  git sprout           !legit sprout
  git sync             !legit sync
  git switch           !legit switch
  git resync           !legit resync

[wkentaro]

This <= is because max should include the biggest number.

[wkentaro]

strip spaces at each line's end, to get correct formatted output.

[wkentaro]

Done.