Indent: add variable to make indent behave as before (no-parens-align)

[pboettch]

As of commit d88bd3e the indent-code is making command-arguments align to the open-parenthesis of the command:

set_property(TARGET foo APPEND PROPERTY
             # with comment
             INCLUDE_DIRECTORIES ${BAR})

This breaks the behavior to previous version of this plugin, where only shiftwidth was added.

We could use a variable to get back the old behavior.