Modify function name
Complete IDyM for robots with flexible joints

Complete Inverse Dynamic Model for robots with flexible joints.
Update direct dynamic model

Update direct dynamic model in `pysymoro/fldyn.py` to efficiently
compute the direct dynamic model for fixed base robots along with
floating base robots.
Update function names and their calls accordingly.
Move base acceleration computation

Move base acceleration computation outside the recursive loops.
Rename `pysymoro/fldyn.py` to `pysymoro/nealgos.py`

Update calls accordingly.