Explicate dependency on util package

[Mr][] and [Mop][] serve a similar function to [Browserify][] but
supports refresh-to-reload during development using Mr and whole package
application transformation with Mop. Thus a build step is not necessary
during development, and transforming packages for use in production does
not require any configuration changes in source. These loaders support
Node.js modules and packages with very high fidelity, inferring where
npm installed packages, but with one major caveat, unlike Browserify, Mr
does not assume that the running environment has Node.js global modules.
This is easily rectified by explicating the dependency on the
corresponding package from npm.

[Mr]: https://github.com/montagejs/mr
[Mop]: https://github.com/montagejs/mop
[Browserify]: https://github.com/substack/node-browserify
Merge pull request #435 from kriskowal/mr

Explicate dependency on util package
fake timer creation returns an object having .ref() and .unref() calls, so that
nodejs timer functionality can be supported
update fake timer addTimer to return object or number based on calling
setTimeout, and checking its type.  this should give mock returns consistent
with the underlying interpreter.
Fix an issue passing NaN to spy#calledWith (Issue #441)
Fix Travis build

Travis seems to have an older npm version installed and does not know
about ^ yet. Changed the dependency to the good old >= thing work
around this.
update timer code per suggestions from @mantoni, pull request #437
Merge pull request #437 from benfleis/master

fake timer creation returns an object having .ref() and .unref() calls
1.9.1
Fix strangely worded tests
Fix wrapMethod error handling

sinon.wrapMethod was actually failing with this error when the property
wasn't defined:
"Cannot read property 'restore' of undefined"

It tried to access wrappedMethod.restore despite results of previous
check if the wrappedMethod is a function.

This commit fixes this issue and the corresponding test.
Merge pull request #449 from deltaidea/fix-wrapMethod

Fix wrapMethod error handling
AMD spec calls for require.amd to be an object

Fixes #448
fix fakeServer.respond() in IE8 by properly allowing queue to be spliced
Fix clearTimeout() for Node.js mode
Merge pull request #451 from Medium/xiao-fix-clearTimeout-for-nodejs

Fix clearTimeout() for Node.js mode
update 'returns numeric id' tests for setTimeout, setImmediate and setInterval
Merge pull request #452 from benfleis/master

update 'returns numeric id' tests for setTimeout, setImmediate and setInterval
Remove extra `module.exports.assert`

`module.exports.assert` is already assigned at line 352. Remove the extra line of setting it again.
Merge pull request #454 from GCheung55/patch-1

Remove extra `module.exports.assert`