Add new platforms for CI testing
Add new platforms for CI testing

Add new platforms for CI testing, e.g. other versions of Ubuntu, RedHat, etc.

Defaults still to run only 'Windows_NT', 'Ubuntu14.04', 'CentOS7.1', 'OSX' every
PR, and allows one to call:

* "test all outerloop please" - to test all outerloops
* "test all innerloop please" - to test all innerloops
* "test {inner|outer}loop {os} please" - to test a particular innerloop

dotnet/wcf,mconnew/wcf,zhenlan/wcf,shmao/wcf,StephenBonikowsky/wcf,dotnet/wcf,StephenBonikowsky/wcf,dotnet/wcf,ericstj/wcf,MattGal/wcf,iamjasonp/wcf,mconnew/wcf,KKhurin/wcf,hongdai/wcf,ElJerry/wcf,shmao/wcf,zhenlan/wcf,mconnew/wcf,imcarolwang/wcf,KKhurin/wcf,imcarolwang/wcf,ericstj/wcf,imcarolwang/wcf,iamjasonp/wcf,MattGal/wcf,ElJerry/wcf,hongdai/wcf