Update README to only suggest running browser tests from a webserver

Since the tests will actually fail when loaded from the file system, let's suggest to developers that they run the browser tests from a webserver instead
Add basic phantom runner
Fix #492 by upgrading formatio and setting a limit
Close #458 by proving that there is no failure

This pull request closes issue #458 by implementing a test that shows that it is possible to stub fs.readFileSync. I've run the tests on node 0.10.25 and 0.10.29 and cannot reproduce the bug.
Merge pull request #528 from mroderick/issue-458-stub-readFileSync

Close #458 by proving that there is no failure
Merge pull request #524 from mroderick/update-readme-about-testing-in-browsers

Update README to only suggest running browser tests from a webserver
Merge pull request #525 from mroderick/fix-issue-492-limitChildrenCount

Fix #492 by upgrading formatio and setting a limit
Merge pull request #530 from neonstalwart/fix-amd

revert fe586d4 and find another way to address #507
Merge pull request #522 from mroderick/add-phantom-runner

Add PhantomJS runner
refactor lib/sinon to attach API to an object

due to circular dependencies, sinon needs to be defined on `exports`.
fake_xml_http_request needs sinon to exist

due to the call to sinon.extend, there's no point in declaring the sinon global if it doesn't already exist
return sinon from makeApi
explicit dependencies for fake_xml_http_request
explicit dependencies for event
explicit depenencies for fake_server
explicit dependencies for fake_server_with_clock
explicit dependencies for fake_timers
explicit dependencies for fake_xdomain_request
add event dependency for fake_xml_http_request
explicit dependencies for assert