Increase file system watcher buffer size.
Increase file system watcher buffer size.

This dramatically decreases the number of OverflowException on
heavily changing file system (i.e. during a build) at the cost
of some memory (2 MB instead of 60 KB).

Fixes bug #41

chromium/vs-chromium,chromium/vs-chromium,chromium/vs-chromium,chromium/vs-chromium