Adds 'Continuous Integration' to the docs.
Adds 'Continuous Integration' to the docs.

Addresses #504 by adding a 'Continuous Integration' section to CONTRIBUTING.md
that describes the new build server (#456) and the new build script (#523).

hackle/AutoFixture,AutoFixture/AutoFixture,Pvlerick/AutoFixture,adamchester/AutoFixture,sbrockway/AutoFixture,adamchester/AutoFixture,dcastro/AutoFixture,dcastro/AutoFixture,sergeyshushlyapin/AutoFixture,sergeyshushlyapin/AutoFixture,hackle/AutoFixture,zvirja/AutoFixture,sbrockway/AutoFixture,sean-gilliam/AutoFixture