Convert builtin help to reStructuredText source files

Run the convert-help.bash script to convert documentation:

 ./convert-help.bash "/path/to/CMake-build/bin"

Then remove it.

Help/command/qt_wrap_cpp.rst

@@ -0,0 +1,12 @@
+qt_wrap_cpp
+-----------
+
+Create Qt Wrappers.
+
+::
+
+  qt_wrap_cpp(resultingLibraryName DestName
+              SourceLists ...)
+
+Produce moc files for all the .h files listed in the SourceLists.  The
+moc files will be added to the library using the DestName source list.