Xbee

* Add error_callback function to XBeeBase.
* If an error_callback method is given to the XBeeBase constructor (in addition to the callback method), a new thread will automatically be spawned. This thread will read from the serial port and call the error_callback when an unexpected Exception (not ThreadQuitException) is raised while waiting for serial data. This generally indicates that the XBee serial interface needs to be reconnected.

* Support for XBee ZB devices significantly improved.
* Now raises a KeyError with a useful message when a response that looks like a command is received. This helps debug devices that are not in API mode.
* Improper lengths for the ZigBee tx_explicit cluster and profile fields have been corrected.
* Removed auto-testing distutils extension for lack of easy cross-version compatibility.
* Now compatible with both Python 2.X and Python 3.X.
* Fixed bug in APIFrame.escape().
* Fixed crash where a failed call to Serial.read() could return nothing.
* Packet-parsing subsystem generalized to allow for much more general parsing behavior.
* ZigBee now parses IS command responses.
* Node Discover responses for ZigBee devices are now parsed.
* Added tests for escaped API communication.
* Fixes issue 31 on Google Code: parameter information for lowercase nd or is commands were not parsed.
* Closes issue 35, as reported by Mark Fickett.
* If an empty frame is received from a device, it is ignored.
* Removed deprecated build process files.
* Backported parsing of IS AT command response as I/O data from ZigBee devices.
* BACKWARDS-INCOMPATIBLE CHANGES (See the documentation for details):
* XBee IS "Force Sample" AT response (and Remote AT Response) 'parameter' value is no longer raw; it is parsed as I/O samples.
* ZigBee IS "Force Sample" AT response (and Remote AT Response) 'parameter' value is no longer raw; it is parsed as I/O samples.
* ZigBee ND "Node Discover" AT response (and Remote AT Response) 'parameter' value is no longer raw; it is parsed into a node discover dictionary.

* Added preliminary support for XBee ZB devices; thanks Greg and Brian!
* Improved & unified sample data header parsing code.
* Improved documentation.

* Fixed bug where _write() call on a serial object should have been write().

* Added support for I/O sample data packet with 64-bit addressing.
* Fixed bug where threading.Thread library was not properly initalized in all use cases.
* Added initial documentation.
* Properly included distutils_extensions.py in source distribution archives.

* Implemented Dispatch helper as xbee.helpers.dispatch.
* Dispatch allows one to filter incoming packets between one or more handler functions. This simplifies application logic which must handle more than one packet type. Automated tests are now run as a part of the build process.
* nose must be installed for this feature to operate. If it is not installed, the tests will be skipped and a warning will be generated.
* A 'test' command has been added to setup.py.