Check if fixed to ICRF matrix is defined when computing approximate LVLH.
Merge branch 'master' into approximateLVLH
If computeFixedToIcrfMatrix returns undefined, use computeTemeToPseudoFixedMatrix.
DynamicPositionProperty falls back to computeTemeToPseudoFixedMatrix if computeIcrfToFixedMatrix fails due to lack of EOP data.
Modify convertToFixed to return a vector when computeIcrfToFixedMatrix returns undefined.
Make paths fallback to `computeTemeToPseudoFixedMatrix` as well.
Merge pull request #869 from AnalyticalGraphicsInc/approximateLVLH

Approximate LVLH