prepare 4.9.1

CHANGELOG.txt

-4.9.1 (Work-in-progress): relax tolerance on curve parametrization match for
-periodic meshing; activate IncludeBoundary by default in Restrict field;
-downgraded compiler for official Linux to gcc 6 to improve compatibility with
-older systems; small bug fixes (view tag generation with zero tag,
-model/setTag).
+4.9.1 (December 18, 2021): relax tolerance on curve parametrization match for
+periodic meshing; enable extruded boundary layers on generic model entities;
+activate IncludeBoundary by default in Restrict field; downgraded compiler for
+official Linux releases to gcc 6 to improve compatibility with older systems;
+small bug fixes (view tag generation with zero tag, model/setTag).
 
 4.9.0 (December 3, 2021): new initial 2D meshing algorithm; new quasi-structured
 quad algorithm; improved handling of imperfect curve reparametrization on

doc/gmsh.html

@@ -98,17 +98,17 @@ Public License (GPL)</a>:
 <ul>
   <li>
     <div class="highlight">
-      Current stable release (version 4.9.0, 3 December 2021):
+      Current stable release (version 4.9.1, 18 December 2021):
       <ul>
         <li>Download Gmsh for
-          <a href="bin/Windows/gmsh-4.9.0-Windows64.zip">Windows</a>,
-          <a href="bin/Linux/gmsh-4.9.0-Linux64.tgz">Linux</a> or
-          <a href="bin/MacOSX/gmsh-4.9.0-MacOSX.dmg">macOS</a> <a href="#1"><sup>*</sup></a>
-        <li>Download the <a href="src/gmsh-4.9.0-source.tgz">source code</a>
+          <a href="bin/Windows/gmsh-4.9.1-Windows64.zip">Windows</a>,
+          <a href="bin/Linux/gmsh-4.9.1-Linux64.tgz">Linux</a> or
+          <a href="bin/MacOSX/gmsh-4.9.1-MacOSX.dmg">macOS</a> <a href="#1"><sup>*</sup></a>
+        <li>Download the <a href="src/gmsh-4.9.1-source.tgz">source code</a>
         <li>Download the Software Development Kit (SDK) for
-          <a href="bin/Windows/gmsh-4.9.0-Windows64-sdk.zip">Windows</a>,
-          <a href="bin/Linux/gmsh-4.9.0-Linux64-sdk.tgz">Linux</a> or
-          <a href="bin/MacOSX/gmsh-4.9.0-MacOSX-sdk.tgz">macOS</a> <a href="#1"><sup>*</sup></a>
+          <a href="bin/Windows/gmsh-4.9.1-Windows64-sdk.zip">Windows</a>,
+          <a href="bin/Linux/gmsh-4.9.1-Linux64-sdk.tgz">Linux</a> or
+          <a href="bin/MacOSX/gmsh-4.9.1-MacOSX-sdk.tgz">macOS</a> <a href="#1"><sup>*</sup></a>
         <li>Download both Gmsh and the SDK with pip: '<code>pip install --upgrade
             <a href="https://pypi.org/project/gmsh/">gmsh</a></code>'
       </ul>