Have a mean to disable the request timeout.

The current implementation of `requestTimeout` will always set a request timeout, either with a custom value or the default value. But sometimes this is not what I want. Especially when I run long running stored procedures with a variable running time, I don't want the request timeout to be specified. This patch gives me the possibility to disable the request timeout by setting the configuration option `requestTimeout` to -1. This preserves backwards compatibility and makes disabling the request timeout a conscious decision (which is probably good). Probably the documentation should be updated too.

PS: Sorry for polluting the PR with the white space removal. My editor does this automatically and I haven't noticed. The actual patch is really simple and can be found on line 487 in `src/connection.coffee`. If this is a problem, than I can send a new PR.