Combinatorica as submodule (#1226)

Remove Combinatorica from this repository but include it as a git
submodule from Mathics3-Combinatorical.

As a by-product, version 2.0.0 of Combinatorica is also now available.
An additional CI job is set up to run the Combinatorica tests that we
have (currently for v0.9). These will be expanded soon.
 And possibly we may include v2.0.0 tests as well. 

To be determined if we want the one CI just to run tests for other
packages as well.

.github/workflows/packages.yml

@@ -0,0 +1,40 @@
+name: Mathics3 Packages (ubuntu)
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: '**'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.11']
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+    - name: Install OS dependencies
+      run: |
+        sudo apt-get update -qq && sudo apt-get install -qq liblapack-dev llvm-dev tesseract-ocr remake
+    - name: Install Mathics3 with full dependencies
+      run: |
+        python -m pip install --upgrade pip
+        # We can comment out after next Mathics-Scanner release
+        python -m pip install -e git+https://github.com/Mathics3/mathics-scanner#egg=Mathics-Scanner[full]
+        cd src/mathics-scanner/
+        pip install -e .
+        python -m mathics_scanner.generate.build_tables
+        cd ../..
+    - name: Run Mathics3 Combinatorica tests
+      run: |
+        git submodule init
+        git submodule update
+        remake -x develop
+        cd mathics/packages/Combinatorica-repo
+        pip install -e .[dev]
+        remake -x check

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "mathics/packages/Combinatorica-repo"]
+	path = mathics/packages/Combinatorica-repo
+	url = https://github.com/Mathics3/Mathics3-Combinatorica.git

mathics/packages/DiscreteMath/CombinatoricaV0.6.m

@@ -0,0 +1 @@
+../Combinatorica-repo/Combinatorica/CombinatoricaV0.6.m

mathics/packages/DiscreteMath/CombinatoricaV0.9.m

@@ -0,0 +1 @@
+../Combinatorica-repo/Combinatorica/CombinatoricaV0.9.m

mathics/packages/DiscreteMath/CombinatoricaV2.0.0.m

@@ -0,0 +1 @@
+../Combinatorica-repo/Combinatorica/CombinatoricaV2.0.0.m

mathics/packages/DiscreteMath/Kernel/init.m

@@ -1,3 +1,4 @@
+(* -*- wolfram -*- *)
 (* DiscreteMath`CombinatoricaV0.9 goes with:
 
  	Implementing Discrete Mathematics: Combinatorics and Graph Theory
@@ -12,6 +13,13 @@
 Get[ "DiscreteMath`CombinatoricaV0.6" ]
 Get[ "DiscreteMath`CombinatoricaV0.9" ]
 
+(* The revised edition of the book is:
+*Computational Discrete Mathematics: Combinatorics and Graph Theory in
+Mathematica*, by Sriram V. Pemmaraju and Steven S. Skiena, Cambridge
+University Press, 2003.
+ *)
+Get[ "DiscreteMath`CombinatoricaV2.0.0" ]
+
 (* The below is from https://library.wolfram.com/infocenter/MathSource/6825/
  An alpha test version is at:
  http://www.nic.funet.fi/index/Science/math/mathematica/Logic/RSolve.m