[3.0] code tag changes

[live627]

• wrap code in preformatted html tags
• do the same in the sceditor
• bonus: fix php tag processing in the sceditor
• add buttons for selecting and expanding code blocks with js; don't output them from php
• remove smfSelectText( ) as it is unused now

[ThistleSifter]

For semantics and accessibility, what about replacing the div header with figure/figcaption?

<figure>
    <figcaption>PHP code: <button>Select</button> <button>Expand></button></figcaption>
    <pre><code>$foo</code></pre>
</figure>

[jdarwood007]

@live627 This is in draft. Is that intended?