Format Cargo.toml and update dependencies

[tesuji]

Update various dependencies

% cargo update
Updating crates.io index
RemovingMacTypes-sys v2.1.0Updating block-padding v0.1.3 -> v0.1.4Updating cc v1.0.35 -> v1.0.36Updating cookie v0.11.0 -> v0.11.1Updating core-foundation v0.5.1 -> v0.6.4Updating core-foundation-sys v0.5.1 -> v0.6.2Updating curl v0.4.20 -> v0.4.21Updating curl-sys v0.4.17 -> v0.4.18Updating dtoa v0.4.3 -> v0.4.4Updating filetime v0.2.4 -> v0.2.5Updating git-testament v0.1.4 -> v0.1.6Updating git-testament-derive v0.1.5 -> v0.1.7Updating hyper v0.12.27 -> v0.12.28Updating itoa v0.4.3 -> v0.4.4Updating libc v0.2.51 -> v0.2.54Updating native-tls v0.2.2 -> v0.2.3Adding numtoa v0.1.0Updating openssl v0.10.20 -> v0.10.21Updating openssl-sys v0.9.43 -> v0.9.45Updating proc-macro2 v0.4.27 -> v0.4.29Updating rand_jitter v0.1.3 -> v0.1.4Updating reqwest v0.9.15 -> v0.9.16Updating ryu v0.2.7 -> v0.2.8Updating security-framework v0.2.2 -> v0.3.1Updating security-framework-sys v0.2.3 -> v0.3.1Updating serde v1.0.90 -> v1.0.91Updating serde_derive v1.0.90 -> v1.0.91Updating socket2 v0.3.8 -> v0.3.9Updating syn v0.15.31 -> v0.15.33Updating tar v0.4.22 -> v0.4.24Updating termion v1.5.1 -> v1.5.2Updating tokio v0.1.18 -> v0.1.19Updating tokio-sync v0.1.4 -> v0.1.5Updating tokio-threadpool v0.1.13 -> v0.1.14Updating unicase v2.3.0 -> v2.4.0

[bors]

☔ The latest upstream changes (presumably #1815) made this pull request unmergeable. Please resolve the merge conflicts.