Feature/xpress only (#115)

* remove python script

* remove RTE actions

* fix test_xpress_interface.cc

* remove callback_xpress.py

* revert writing colnames and rownames

* accept suggestion from Mizux

* clean

* change cmake/README.md

* try fix build bazel

* try fix build bazel add MPSWriteError.h

* xpress tests gracefully exit if Xpress not found

* add integer and linear programming test for dotnet python and java

* remove MPSWriteError

* try fix Window build

* remove useless line from CMakeLists.txt

* try fix test under windows

* reformat

* use XPRESS_LP instead of XPRESS for linear programming examples

* tools: add --platform arg when possible

make script more resilient/cross-platform

* [CP-SAT] convert to PEP8 convention

* use XPRSmipoptimize and XPRSlpoptimize instead of XPRSminim and XPRSmaxim (#114)

* use XPRSmipoptimize and XPRSlpoptimize instead of XPRSminim and XPRSmaxim

* clean xpress/environment files

* accept changes: empty char* parameter for XPRS*optimize

* Add test on number iterations with LP basis

* fix gtests flags

* refactor

* suggestions by @flomnes

* remove unwanted files

---------

Co-authored-by: Andrea Sgattoni <andrea.sgattoni@rte-france.com>
Co-authored-by: Laurent Perron <lperron@google.com>
Co-authored-by: Corentin Le Molgat <corentinl@google.com>
Co-authored-by: Andrea Sgattoni <andrea.sgattoni@gmail.com>

examples/java/LinearProgramming.java

@@ -117,6 +117,6 @@ public class LinearProgramming {
     System.out.println("---- Linear programming example with CLP ----");
     runLinearProgrammingExample("CLP", false);
     System.out.println("---- Linear programming example with XPRESS ----");
-    runLinearProgrammingExample("XPRESS", false);
+    runLinearProgrammingExample("XPRESS_LP", false);
   }
 }