Update to FriCAS 1.1.8

Notable changes in FriCAS 1.1.8 (compared to version 1.1.7):

- Improvements of pattern matching integrator, it can now integrate
  in terms of Fresnel integrals and better handles integrals in terms
  of Si and Ci.
- Better integration of symbolic derivatives.
- Better normalization of Liouvillian functions.
- New package for computing limits using Gruntz algorithm.
- Faster removal of roots from denominators.
- New domains for mutivariate Ore algebras and partial differential
  operators.
- New package for noncommutative Groebner bases.
- New domain for univariate power series with arbitrary exponents.
- New special functions: Shi and Chi.
- New package for noncommutative Groebner bases.
- New domain for univariate power series with arbitrary exponents.
- New special functions: Shi and Chi.
- Several aggregates (in particular tables) allow more general
  parameter types.
- New domain for hash tables using equality from underlying
  domain.

Bug fixes, in particular:

- Fixed problem with gcd failing due to bad reduction.
- Fixed series of 'acot' and Puiseux series of several special functions.
- Fixed wrong factorization of differential operators.
- Fixed build problem on recent Mac OS X.

Notable changes in FriCAS 1.1.7 (compared to version 1.1.6):

- Improved integration in terms of special functions.
- Updated new graphics framework and graph theory package.
- Added routines for numerical evaluation of several special
  functions.
- Added modular method for computing polynomial gcd over algebraic extensions.
- Derivatives of fresnelC and fresnelS are changed to agree
  with established convention.
- When printing floats groups of digits are now separated by
  underscores (previously were separated by spaces).
- Added C code for removing directories, this speeds up full
  build and should avoid build problems on Mac OSX.

Bug fixes, in particular:

- Series expansion now handle poles of Gamma.
- Fixed derivatives of meijerG.

(asau)