Merge pull request #1 from hschilling/atlas_helicopter_branch

Atlas helicopter branch - properties and more...
finished conversion of vortexwake
Merge branch 'master' of git@github.com:thearn/Atlas.git
fixed 2 tests
finished core of vortex conversion
finished vortex wake calculation
comments & readability
working on structures modeule
working on structures module
create structures assembly & components
Merge branch 'master' into dev
working on structures testing:  MassProps done, debugging FEM
still working on structural testing, fix QuadSpar connections
Structural runs, not correctly but it runs
fix up some connections in Structural
make dist
-	Stubbed in Failure component
-	Made Strain a VarTree
-	Split out Strains component from FEM
-	Added matlab test data for Strains  and FEM testing
-	Added test for Strains
-	Got both FEM & Strains tests to pass
-	Integrated structures test still fails and Failure needs to be implemented yet
re-makedir
debugging Structures assembly
use MATLAB data to test mass calculations
add MATLAB data for full up structures calculation
debugging full up structures calculation
fix JointSparProperties and Mass xCG calc...  full-up test now successful
working on Failures component