Increasing the amount of inotify watchers for osx and linux

[paolomainardi]

We need it for making Angular serve live-reloading feature to work when handling a lot of files, which is a quite common scenario.

We basically need to make the configuration permanent, like this:

$ echo fs.inotify.max_user_watches=524288 | tee -a /etc/sysctl.conf
$ sudo sysctl -p