Modify the display of histograms: now can use subplots to display several...

Modify the display of histograms: now can use subplots to display several histograms on one page, can no longer display both dev and eval histo at the same time, can control the number of columns in the legend
6 jobs for title in 74 minutes (queued for 6 seconds)
Status Job ID Name Coverage
  Build
passed #134541
docker
build_linux_27

00:15:16

82.0%
passed #134542
docker
build_linux_36

00:09:20

82.0%
passed #134582
macosx
build_macosx_27

00:50:40

82.0%
passed #134583
macosx
build_macosx_36

00:49:41

82.0%
failed #134543
macosx
build_macosx_27

01:00:01

failed #134544
macosx
build_macosx_36

01:00:01