Different encoding for symbols in external links

Preconditions
User has admin permissions, is logged in, is in admin mode

Steps to reproduce
1. Go to external links editor - press "Add"
2. Fill all fields with

<script>alert("Hi")</script>

3. Press "Save" button, close external links editor.

Actual result
Just added link has following code:

<li><a id="small-screen-external-link-9696" data-original-title="&lt;script&gt;alert(&#034;Hi&#034;)&lt;/script&gt;" href="http://&lt;script&gt;alert(&#034;Hi&#034;)&lt;/script&gt;">&lt;script&gt;alert(&#034;Hi&#034;)&lt;/script&gt;</a></li>

I.e. > is escaped, " is transformed, / is not transformed.

Expected result
All special symbols (including slashes, backslashes, quotes and so on) in external link should be encoded equally.
So if we use escaping - all special symbols should be escaped (without using something like ").