Handle OSError exception in process_IN_CREATE.

close #76
Update Travis conf.

Closes #74
Fix /proc inotify interfaces.

There was a bug preventing the variables to be assigned a new
value.

The operations accessing (get and set) these interfaces now return
an OSError exception on failure.

Closes #73
Add WatchManager attribute to ignore events.

A new boolean attribute ignore_events (False by default) can be set
to True in order to ignore reported events. Note that Watch descriptors
are still valid and events are still received but there are ignored
and not processed. Processing is resumed by re-assigning False to this
attribute.

Closes #44
Stub support for Pyinotify on FreeBSD.

I don't have any FreeBSD system, so test it and report any issue
with this code.

Closes #64
Improve example daemon.py.

Closes #77
Typo.
Add new classifiers.

Closes #79
Fix ExcludeFilter docstring examples.

Closes #81