Issue 400b: fix for documentation versioning (#531)

* add documentation versioning based on git branches

* add escape characters to reg exp

* fix typo

* add missing index.html

* add merging master to docs_stable on tag creation

* fix the project path for branching end merging documentation

* do not remove all versions of docs

* create the docs directory if it does not exist

Author: jkotan

Jenkinsfile

@@ -201,8 +201,7 @@ builders = pipeline_builder.createBuilders { container ->
           git fetch
           git checkout gh-pages
           git pull
-          shopt -u dotglob && rm -rf ./*
-          mkdir -p ./latest
+          mkdir -p ./latest && shopt -u dotglob && rm -rf ./latest/*
           mv -f ../build/doc/build/* ./latest/
           mv -f ../build/doc/doxygen_html ./latest/doxygen
           mv -f ../build/doc/index.html ./
@@ -238,8 +237,7 @@ builders = pipeline_builder.createBuilders { container ->
           git fetch
           git checkout gh-pages
           git pull
-          shopt -u dotglob && rm -rf ./*
-          mkdir -p ./${version}
+          mkdir -p ./${version} && shopt -u dotglob &&  rm -rf ./${version}/*
           mv -f ../build/doc/build/* ./${version}/
           mv -f ../build/doc/doxygen_html ./${version}/doxygen
           find ./ -type d -name "CMakeFiles" -prune -exec rm -rf {} \\;