doc(windows-msys2.md): add

[skip ci]
test
start adding flowstar
added taylor model holder in egraph. next: put odes into the holder at parsing time. question: pointers to tms or not.
taylormodels folder
int vs unsigned
modifying parser
parse holders for partial ODEs
built connect and pintegral at the egraph level. next is icp_solver
level.
temp
minor
minor
temp
reverting to the bare minimal
Fixed: order in Enode types matter, has to be the same in declaring
newsymbols.
main parts of pintegral
pint roughly there
need to clean up on taylor models...
sqrt
print sqrt