Reorder the preferred fonts list

[jwiggins]

Closes #406

Since "Lucida Grande" doesn't come with all four styles on macOS, we're demoting to lower in the list of sans-serif family names. "Arial" and "Verdan" both have all the styles on macOS and Windows.

(Also adding "Helvetica Neue" to the mix just for funsies)

[rahulporuri]

LGTM

[jwiggins]

The new default font results (excuse the magic numers for style):

In [1]: from kiva.fonttools import Font                                         

In [2]: Font(style=0).findfont()                                                
Out[2]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=0)

In [3]: Font(style=1).findfont()                                                
Out[3]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=1)

In [4]: Font(style=2).findfont()                                                
Out[4]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=2)

In [5]: Font(style=3).findfont()                                                
Out[5]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=3)

In [6]: Font("modern", style=0).findfont()                                      
Out[6]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=0)

In [7]: Font("modern", style=1).findfont()                                      
Out[7]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=1)

In [8]: Font("modern", style=2).findfont()                                      
Out[8]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=2)

In [9]: Font("modern", style=3).findfont()                                     
Out[9]: FontSpec(/System/Library/Fonts/HelveticaNeue.ttc, face_index=3)

[jwiggins]

Thanks for the review

[rahulporuri]

and here's what i see on windows -

>>> from kiva.fonttools import Font

>>> Font(style=0).findfont().filename
'c:\\windows\\fonts\\arial.ttf'

>>> Font(style=1).findfont().filename
'c:\\windows\\fonts\\arialbd.ttf'

>>> Font(style=2).findfont().filename
'c:\\windows\\fonts\\ariali.ttf'
>>> Font(style=2).findfont().face_index
0

>>> Font(style=3).findfont().filename
'c:\\windows\\fonts\\arialbi.ttf'

>>> Font("modern", style=0).findfont().filename
'c:\\windows\\fonts\\arial.ttf'

>>> Font("modern", style=1).findfont().filename
'c:\\windows\\fonts\\arialbd.ttf'