Merge pull request mxcl#1090 from mxcl/xcode10.3

[ci] Xcode 10.2 -> 10.3

Merge pull request mxcl#1078 from RomanPodymov/master

Add AnyPromise.wait

Merge pull request mxcl#1074 from Igor-Palaguta/GuaranteeSequenceOper…

…ators

Add guarantee sequence utils

[travis] Use CocoaPods ~> 1.7.0; update submodules

Merge pull request mxcl#1045 from GarthSnyder/wrapper-revamp

Wrapper revamp

[ci skip] Fix deploy

.some(6.8.4)

mxcl.github.io|promisekit.org -> mxcl.dev

* Fixes broken links
* Corrects spelling

[skip ci]

Tag 6.8.3

Tag 6.8.2