Add timeout option to all read calls

[pfrazee]

I need to be able to control whether and how long the timeout for read calls works. At a glance that'll need to cover:

• access
• stat
• lstat
• readdir
• readfile
• createReadStream

[jimpick]

Currently, when offline and attempting to do a .readFile() when the data isn't yet synced will cause the node process to exit without throwing an exception.

I did a little test and if we set a default timeout and pass it through, it will throw a nice timeout error before node exits.

[eu1444]

Has there been any movement on this issue? Having the ability to timeout calls seems pretty essential.

[eu1444]

I think a timeout for download is important as well.