I'm not sure what you mean by installing, are these native JavaScript libraries or RapydScript ones? RapydScript can use native JavaScript libraries same way JavaScript itself would, with no installation required. You will still need to include them on the page, something like this:
<script src="javascript_library_you_want_to_use.js"></script>
<script src="rapydscript_code_after_compilation.js"></script>
If these are RapydScript libraries, you can do the same method as above (just compile them separately and include both on the page) or better yet, import them into your code directly (see the manual on importing:
http://rapydscript.pyjeon.com/#header-tag-doc24).
For an example of this second way of importing, see how the same Paint app (in paint.pyj) imports the Drawing.pyj library