This version (for MediaWiki 1.19) has some changes since previous versions:

* rendering options have been reduced to just 'Always PNG' and 'Leave it as TeX'
** all other rendering options will merge to PNG.
* initial experimental support for integrating MathJax client-side rendering

See the README in the math subdirectory for more info on setting up the
low-level conversion tools.

MathML support:
If you prefer MathML rather than images you can use LaTeXML to convert the
math tags to MathML. To use that feature you have to enable LaTeXML by setting
$wgUseLaTeXML = true;
It is possible to choose LaTeXML as default option (for anonymous user) by setting
$wgDefaultUserOptions['math'] = MW_MATH_LATEXML;
in the LocalSettings.php file.
The LaTeXML option requires php5-curl to be installed. Without php5-curl no proper
error handling can be guaranteed.

MathJax configuration:
Client-side configuration of MathJax can be done by specifying a mathJax.config
table, which takes a table as described in:
http://docs.mathjax.org/en/v1.1-latest/options/index.html#configuration

Example:
if ( typeof mathJax === 'undefined' ) {
  mathJax = {};
  mathJax.config = {
    showProcessingMessages: true
  };
}

For testing your installation run
php tests/phpunit/phpunit.php extensions/Math/tests/
from your MediWiki home path.