Fix Coverity reported bugs: uninit var and illegal dereferencing.
Add expression sampling tests.
Exclude all header files from Coveralls reports.
Add tests for NULL top due to house event. In addition, add a test call graphing
of house events.
Fix Coverity reported bug of dereferencing wrong iterator.
Refactor sampling function for uncertainty analysis.
Add tests for NOR and NAND gates as children.
Add test input file with very long minimal cut set.

This case must be reported by dividing the cut set into chunks that fit
into a screen.
Add a test for non-coherent MCUB request.
Use the general gate function for complex top gate expansion.

Previously, top gates were treated in the UnrollGates() function while
the same functionality exists in the general UnrollGate() function.
Add a test for many house event propagation scenarios.
Correct input files for name and definition clash detection.
Add a test for constant gate propagation due to complement basic events.
Add input files that describe the issue #92.

The subtle unity of generated minimal cut sets are not detected and
reported correctly.
Update readme, todo, and documentation with non-coherency and
algorithms.
Add benchmark tests for the Chinese fault tree from XFTA.
Implement a new algorithm for cut set generation.

A new walker algorithm is implemented that is supposed to generate cut
sets from a fault tree faster than the previous algorithms. The
minimality detection is not optimized.
Apply the cut set minimization optimization from the previous algorithm.

The code from the previous algorithm is used to minimize generated cut
sets. This provides a bit of performance improvement.
Decrease non-deterministic performance with the new algorithm. Provide
speed recordings. Fixes #89.

The new algorithm reduces non-determinism in comparison to the previous
implementation of the MOCUS-like algorithm.
Cleanup the code and refactor gate joining and constant gate processing
in the indexed fault tree class.