better examples for std/inotify

[Archargelod]

Previous example wouldn't run unless std/posix was imported and it wasn't mentioned anywhere in the docs.

Other changes in the example:

• replaced magic number with constant MaxWatches .
• changed seq buffer to array, because length is already constant + pointer is a bit nicer: addr seq[0] vs addr arr
• added example for getting a cstring name value from InotifyEvent struct with explicit cast.
• added a bit more description to inotify_init1 (copied from man inotify(7))