textile output does not properly escape + and - characters

[daphnediane]

Converting to textile does not properly escape + and - characters which means that they can get interpreted as formatting. + should probably be encoded to + and - to -

Testcase:

echo "<p>&#43;x+ &#45;y-</p>" | pandoc --from=html --to=textile | pandoc --from=textile --to=html
<p><em>x</em> <del>x</del></p>