Add .gitmodules file to fix errors reported by SourceTree when checking out releases. Somehow these definitions came across in a recent objectstore merge but the relative paths were wrong for our nested structure.

AndyDentFree · AndyDentFree · commit d4ec5d51e101 · 2016-04-02T01:36:57.000+08:00
diff --git a/.gitmodules b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "external/pegtl"]
+	path = wrappers/src/object-store/external/pegtl
+	url = https://github.com/ColinH/PEGTL
+[submodule "external/catch"]
+	path = wrappers/src/object-store/external/catch
+	url = https://github.com/philsquared/Catch
