Default font on macOS doesn't have italic

[achabotl]

The default font on macOS doesn't have italic. Neither does the "modern" font, which is used by default by Chaco. It defaults to Lucida Grande, which only has regular and bold styles. It might be time to consider a new default. San Francisco is not yet installed by default on macOS.

>> from kiva.fonttools import font
>>> f = font.Font()
>>> f.findfont()
'/System/Library/Fonts/LucidaGrande.ttc'
>>> modern.findfont()
'/System/Library/Fonts/LucidaGrande.ttc'
>>> modern = font.Font('modern')
>>> modern.findfont()
'/System/Library/Fonts/LucidaGrande.ttc'
>>> !ls /System/Library/Fonts/LucidaGrande*
/System/Library/Fonts/LucidaGrande.ttc