Included new constraints for the QT limits based on the PR interval, and modification of the measurement variance of the Kalman filter if the measured QT value is abnormally high or low

Implemented an Adaptive Kalman Filter based on the measurement difference wrt the expected QT value.

Improved subsumption reasoning when information about consecutive observations is available. The knowledge base has been also adapted to allow tracking of rhythm and intervals information with each new heartbeat

Conflicts:
	fragment_processing.py
	record_processing.py

safer implementation. Now the merging strategy seems to work ok,
improving the version without it.

Working version that is almost ready to enable the merging strategy.

Adaption of the 'extract_waves.py' script to include amplitude information for all individual waves.

Fix bug in the use of popitem method of SortedDict class due to different behavior from blist to sortedcontainers

Solved a bug in the pattern definition, and defined a new annotation format to include more relevant information

Included P-wave delineation information. Interpretation strategy changed to a more efficient greedy search, but there are still some bugs

Changed dependency from 'blist' package to 'sortedcontainers', and advances in new reasoning methods.

model of the 'interpretation' class, removing all the unnecessary
information and giving more importance to the focus of attention.

http://solutionoptimist.com/2013/12/28/awesome-github-tricks/

Readme updated to include a visual result of an interpretation.

The interpretation process should be faster, but there may be some
coverage penalties.