Update `syn`, `quote` and `proc-macro2`#217

Merged

bors-servo merged 2 commits intoservo:masterfrom

hcpl:update-syn-quote-proc-macro2

Apr 10, 2018

Commits on Apr 1, 2018

Update `syn`, `quote` and `proc-macro2`
hcpl
committed

Commits on Apr 10, 2018

Increment version numbers of affected crates
hcpl
committed