casadi: full -> dense, added sparse
add user options to NlpSolverStuff
rename Jec -> JVec
use MX and call for dynamics constraint
use MX call for dynamics and covariance propogation in direct collocation

this also fixes the broken covariance propogation
move casadi options and init into their own modules
added d2s and expand
break up dynamics and path constraint functions
move Num instances of J into its own module, export Dyno.View
split now doesn't do binary tree
cat now doesn't do binary tree