Added Ipopt-3.13.4

  - It is actually addded in the commits just before this one. Squashed
    and added to the 3rdParty tree.

  - Ipopt matches stable 3.13 branch and modified as follows:

    - We took https://github.com/rjodon/coinor-ipopt-with-cmake
        which is based on 3.13.0

    - Rebased the changes from that repository on top of
        https://github.com/coin-or/Ipopt.git stable/3.13
        which is at 3.13.4 now

    - Modified the cmake configuration heavily.
    - Added MUMPS 4.10.0 by default
    - Added CMake support for MUMPS

  - All of this is done and recorded in the repository
    https://github.com/mahge/coinor-ipopt-with-cmake ipopt-cmake-3.13.4

  - Finally this last repository is squashed and added to
    OMCompiler/3rdParty

  - Ipopt is now configured and compiled using CMake.

Ipopt.txt

@@ -1 +1 @@
-git subtree add --squash --prefix Ipopt https://github.com/coin-or/Ipopt.git stable/3.12
+git subtree add --squash --prefix Ipopt-3.13.4 https://github.com/mahge/coinor-ipopt-with-cmake.git ipopt-cmake-3.13.4