Auto-escape all output from PHP

See here: https://github.com/xmalloc/php-auto-escape

Though, we restore unescaped output for print,echo.printf,...

Had to manually apply some diffs to get it to work with php 5.4
For the functions that were copied, re-copy them with the new php 5.4
implementations and change the prints to print_escape.
Make PHP short tags use their own lexer token

Instead of modifying the existing T_ECHO
Add new php "raw" short tag

It does no auto-escaping at all but functions the same otherwise.
Tests: add for __auto_escape and <?raw=
Simplify zend_print_zval_escape

No need to copy code when an if and a function-call will work
escape_write: do it right

Move the function to where the other output functions are.
Make it use the C interface to the escaping function,
not the slow php one.
AutoEscape: fix spelling errors in tests
AutoEscape: remove __safe function

It's not really needed now that we are only escaping <?= tags
AutoEscape: remove ini-setting function

It was almost exactly the same as ini_set(), so what's the point?
AutoEscape: improve comments in php.ini
php_escape_html_entities make 'old' param const

None of these functions modify the old string so lets make it const.
Particularlay because we need to pass it a 'const char *' from the
escape_write function
AutoEscape: remove one function call.

No sense in calling a function that just calls another function,
let's inline-it.
AutoEscape: add __auto_escape_flags ini setting

To allow modification of the flags param used with htmlspecialchars.
Merge auto-escape-short-tags (#3) into ifixit-production

Auto escape short tags (it works!)

Short tags `<?=` escape html chars if `__auto_escape` is set to 1.

New raw tags `<?raw=` don't escape html chars even if `__auto_escape` is set to 1.

With tests!