First work on Graph SLAM that inherits SLAM interface. Still some work to do. Have to discuss with Dennis
issueID #10
Created an EkfSLAM class implementing the generic SLAM interface. Added lots of TODO comments in locations where I saw possibility for optimization.

Only adapted the algorithm-related code to the new interface, did not yet change the test code to conform to the new interface, so test code is broken.

IssueID #10
The algorithm now cleans up all old and already processed data right before returning a call to run_slam. This should greatly improve speed of on-line SLAM, since it allows the algorithm to continue where it ended in previous calls.

IssueID #10
Changed SLAM interface to have a single method for sending both types of data.

IssueID #10
Changed Graph SLAM implementation to match the interface of SLAM class. Basically changed two sending data methods into one.
issueID #10
Small changes again in order to match interface
issueID #10
Set noise parameters stuff

IssueID #10
working on test code for EKF SLAM
Fixed testing code
set_offline method added to SLAM interface
Added some functionaly and changed some small stuff regarding return statement of runSlam method. Also, added association error variable.
issueID #10
ekf slam stuff
Defined output format for SLAM in comments in SLAM.py

IssueID #10
Merge branch 'refs/heads/feature-10-abstractstuff' into develop