[bug] the width of space isn't proper

[hzhangxyz]

you see, the width of space is twice then its need..

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client environment:

windows 10.0.10586 (64-bit)

chrome 51.0.2704.103 m (64-bit)

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server environment:

Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.63-2+deb7u1 x86_64 GNU/Linux

jupyter 4.1.0

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and in microsoft edge, it's well.

[hzhangxyz]

well , After set chrome's default monospaced font , it is normal....