preserve context of functions from nise: fakeServer, fakeServerWithClock
preserve context of functions from nise: fakeServer, fakeServerWithClock

these functions depend on the original context to run properly

cjohansen/Sinon.JS,mroderick/Sinon.JS,mroderick/Sinon.JS,fatso83/Sinon.JS,cjohansen/Sinon.JS,fatso83/Sinon.JS,mroderick/Sinon.JS,fatso83/Sinon.JS,cjohansen/Sinon.JS