isValidLibraryJavadocRoot(URL rootURL) Tests if the query accepts the root as valid JavadocRoot,
the query accepts the JavaDoc root, if it can find the index-files
or index-all.html in the root.
Tests if the query accepts the root as valid JavadocRoot,
the query accepts the JavaDoc root, if it can find the index-files
or index-all.html in the root.
Parameters: rootURL - the javadoc root true if the root is a valid Javadoc root