OpenPSA documentation finalization. Closes #43.
[skip ci]
Optimization of tree expansion.
ThreeMotor fault tree XML input file.
Closes #44.
2 thread building for Travis-CI.
Exclude some header files from test coverage checks.
Speed improvement for MCS generation.
Rename input tests from fault tree to risk.
Review of event and superset tests.
Rename FaultTreeAnalysisTest to RiskAnalysisTest.
Refactoring and initial test setup for Fault Tree.
Performance improvement for Probability Calculations.
Introduction of cut-off probability.
Closes #47.
Final separation of Gate, Basic, and House events.
Closes #46.

Deprecation:
- L-model probability calculations.
Refactor analysis initialization code.

New methods of defining gates, basic and house events.
Test call for incorrect cut-off values.
Use find()->second instead of operator[] for maps.
Strange performance bottleneck is discovered.

A bash script provided for performance testing.
The issue is in fault_tree_analysis.cc AssignIndices() function.
The containers for primary and intermediate events seem to have big
influence how the code gets compiled and run.
Many minor fixes after Coverity check.
Separation of tests for FaultTreeAnalysis from RiskAnalysis.

Required refactoring for separation is performed.
Excess header files are removed.
Merge branch 'develop' into gh-source