First complete implementation of the fault recurrence calculator

First complete implementation of the fault recurrence calculator
Includes:
1) Active Fault Model (wrapper class for a set of mtkActiveFaults)
2) Active Faults - representation of an active fault source with recurrence calculators
3) Yaml reader
4) Tectonic regionalisation representation

Includes enumerated logic tree calculator supporting (via sets of tuples with value and weights) epistemic uncertainty in: 
i) Slip rate
ii) Shear Modulus
iii) Magnitude Scaling Relation
iv) Magnitude Scaling Relation Uncertinty
v) Displacement to Length Ratio (only used in Anderson & Luco (Area Mmax) calculator)
vi) Magnitude frequency distribution model

For logic tree can collapse branches or enumerate sources