Uncast data before writing out
Uncast data before writing out

Copied from
https://github.com/dougfelt/glyphslib/commit/b6f1024cbdb105610cc3dee8a0cd3d55612cc420

Reverts the str() cast introduced in 95e9c1c13025d7b68fbf6b3414a7877e6743aba0

googlefonts/glyphsLib,googlei18n/glyphsLib