Fixes reading Type1 FontBBox data for usWin values

Closes
#3470 Sum in this PDF not displayed correctly 4-font-windows 4-hwa-off
#2704 Sum and integral symbol cut off in half on Windows 3-pdf-broken 4-font-windows 
#2834 LaTeX square root 4-font-windows 4-hwa-off
#2833 Issue rendering pdf 4-font-conversion 4-hwa-off
https://bugzilla.mozilla.org/show_bug.cgi?id=875205
https://bugzilla.mozilla.org/show_bug.cgi?id=855995