Escape labels for jqplot charts

Escape single- and double-quotes as needed in the generation of the
HTML/JavaScript for the jqplot charts to avoid JavaScript errors.

Author: Aaron Lindsay <aaron@aclindsay.com>

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23754 57a11ea4-9604-0410-9ed3-97b8803252fd
Drop old ampersand subsitution in a couple of reports

It's not needed anymore with jqplot which already takes care of it.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@23755 57a11ea4-9604-0410-9ed3-97b8803252fd