Update CI badges in README (#1201)
Update CI badges in README (#1201)

A couple were pointed to bogus locations, and all were pointed to the old domain rather than the new `ci.dot.net`.

Added Ubuntu 16.04 column.

New markdown was copy/pasted from Jenkins' "Markdown (without view)" from each job's "Embeddable Build Status" link.
mono/msbuild,sean-gilliam/msbuild,cdmihai/msbuild,Microsoft/msbuild,sean-gilliam/msbuild,Microsoft/msbuild,Microsoft/msbuild,AndyGerlicher/msbuild,sean-gilliam/msbuild,rainersigwald/msbuild,chipitsine/msbuild,rainersigwald/msbuild,jeffkl/msbuild,jeffkl/msbuild,cdmihai/msbuild,rainersigwald/msbuild,mono/msbuild,AndyGerlicher/msbuild,mono/msbuild,AndyGerlicher/msbuild,jeffkl/msbuild,jeffkl/msbuild,Microsoft/msbuild,AndyGerlicher/msbuild,cdmihai/msbuild,sean-gilliam/msbuild,cdmihai/msbuild,chipitsine/msbuild,chipitsine/msbuild,chipitsine/msbuild,rainersigwald/msbuild,mono/msbuild