Procedures for integration in:
1) C(x)          intRat    := proc(f,x) ...
2) C(x)[ln(..)]  intPolLog := proc(f,x,theta) where theta=ln(..)
   intPolLog calls intRat for integration in C(x), or when intRat
   is not available then it uses int.
3) C(x,ln(..))   intRatLog := proc(f,x,theta). Uses intPolLog/intRat
   or uses int when those are not available.
4) C(x)[exp(..),1/exp(..)]
   intLaurentPolExp:=proc(f,x,theta) where theta=exp(..)
   Uses ratsols from DEtools package.
5) C(x,exp(..))  intRatExp:=proc(f,x,theta). Uses intLaurentPolExp.
6) C(x,ln(x), ln(ln(x)+x^2)  intNestedLog(f,x,theta1,theta2)
7) Special functions. Write something to find a minimal operator,
   then apply your integrate_sols, and if you find an r, then
   compute an antiderivative.
8) Write a ratsols for the homogeneous case, L(y)=0.
9) Write a ratsols for the inhomogeneous case, L(y)=h by noting
   that (D-h'/h)(h)=0 therefore if M=(D-h'/h)*L then M(y)=0, so
   the ratsols of L(y)=h form a *subset* of the ratsols of M(y)=0.
   Compute the ratsols of the homogeneous equation with (8), or if
   an implementation of (8) is not available then use ratsols.
10) Write my_mult, myREM, myGCRD for operators.
11) Write myLCLM.