sasview: init at 4.1.2

Sasview is a data fitting and analysis package for small angle
scattering data.  More information can be found at
https://www.sasview.org.

There is some unfortunate cruft to this commit.  SasView uses the
xhtml2pdf python package, which has a specific version of html5lib as
a dependency.  This module manually loads that version into sasview.
I haven't made xhtml2pdf available as its own package due to these
circumstances.

pkgs/applications/science/misc/sasview/default.nix

@@ -0,0 +1,51 @@
+{lib, fetchgit, gcc, python}:
+
+let
+  html5 = import ./myHtml5.nix {inherit python;};
+  xhtml2pdf = import ./xhtml2pdf.nix {inherit python html5;};
+in
+
+python.pkgs.buildPythonApplication rec {
+  name = "sasview-${version}";
+  version = "4.1.2";
+
+  propagatedBuildInputs = with python.pkgs; [
+    bumps
+    gcc
+    h5py
+    html5
+    libxslt
+    lxml
+    matplotlib
+    numpy
+    pyparsing
+    periodictable
+    pillow
+    pylint
+    pyopencl
+    pytest
+    reportlab
+    sasmodels
+    scipy
+    six
+    sphinx
+    unittest-xml-reporting
+    wxPython
+    xhtml2pdf];
+
+  src = fetchgit {
+    url = "https://github.com/SasView/sasview.git";
+    rev = "v${version}";
+    sha256 ="05la54wwzzlkhmj8vkr0bvzagyib6z6mgwqbddzjs5y1wd48vpcx";
+  };
+
+  patches = [./pyparsing-fix.patch ./local_config.patch];
+  sandbox = true;
+
+  meta = {
+    homepage = https://www.sasview.org;
+    description = "Fitting and data analysis for small angle scattering data";
+    maintainers = with lib.maintainers; [ rprospero ];
+    license = lib.licenses.bsd3;
+  };
+}