No such Key error because of '\' in filepath

[RaghuChandrasekaran]

I am getting No such Key error when trying to access files because in filepath a backslash gets added.I saw that there are checks to remove forwardslash so inserted this bit of code to check and remove backslash too.That fixes the problem.

filepath = filepath[0] == '\\' ? filepath.substr(1) : filepath,

In context's url a backslash gets added.

if (this.url.indexOf('/') !== 0) this.url = '/' + this.url;

I have sent a PR #3 with this small change.