beamdyn and orcaflex updates

[ghost]

This pull request updates beamdyn_driver and orcaflex_driver with handling for single precision builds. Currently, building in single precision causes compiler errors in these two module drivers due to type mismatches.

Also in this pull request is an update to BD_CrvExtractCrv which improves upon the arithmetic set up in #31.

All of the BeamDyn updates were adapted from @bjonkman's fork at f/Envision-BeamDyn.

The regression test completed with these results:

96% tests passed, 1 tests failed out of 27

Label Time Summary:
aerodyn14     = 3145.73 sec (7 tests)
aerodyn15     = 14563.32 sec (19 tests)
beamdyn       = 1359.88 sec (2 tests)
elastodyn     = 16350.83 sec (25 tests)
hydrodyn      = 8735.51 sec (7 tests)
map           = 1403.95 sec (3 tests)
moordyn       = 841.59 sec (1 test)
openfast      = 17709.05 sec (26 tests)
regression    =   1.67 sec (1 test)
servodyn      = 17697.20 sec (25 tests)
subdyn        = 6489.97 sec (3 tests)

Total Test time (real) = 3388.56 sec

The following tests FAILED:
	 26 - 5MW_Land_BD_DLL_WTurb (Failed)
Errors while running CTest

It is expected that the test case running BeamDyn would have very small changes in the solution. Further investigation reveals that the three failing channels contained negligible differences in the solutions:

[rafmudaf]

I'm closing this pull request without merge as these changes will be included in a subsequent pull request