Separated Channel class to its own source file
Added GIL lock to duration() and removed GIL lock from datetimeFromTimespec()
Support for events
Fixed support for collection channels
Channel_duration() now works on collection channels
Changed the events member variable in Channel to a set.
Now copies strings in Channel and Event constructors
Fixed support for events, now fills in "unknown" if device or serial number is missing
Added the missing Event class into the module dictionary