Change default LockManager back to nullLockManager.

* This was changed in 926db7c3bdcf8911b5314ffd5c1c7d0064d2734f as a workaround for a testing issue.
* See 8cbd679aac781bdd73038064261736a937645fc1 , which fixes the test harness in core .

Change-Id: Ib57cafee35a699ce875ee4bc8951781e1a37553a
Fix MathRenderer::renderMath.

The call to getRenderer is supposed to be a static method in the same class,
not a global function.

Change-Id: I5d101574b1d67238c6357e154209f2595cb36859
Add and register PHP unit tests for MathSource class

This change adds test cases for the MathSource class and registers a
hook for loading these tests. Also adds documentation about how to run
these tests in README.

Change-Id: Ie58a273326e0353dfa4437b3de21a2393adb5a87
Add unit tests, demonstrating how to stub out deps.

Physikerwelt asked for some guidance on how to write good unit tests for
classes that depend on external resources. I wrote a few to serve as examples
for additional tests. Because they have an ulterior didactic purpose, the
comments are a bit more verbose than I would otherwise like, but despite that
the tests are good enough to merit being merged.

Change-Id: Ifa97eec1a68fb68b4744d1e5b192b410afe5ef68
Only update the cache on cache miss

Change I9b1d68c4faa8d177d8d0088fa1a5879caed4f1fe added an indiscriminant call
to writeCache(). I assume that it was supposed to be regulated by the check for
$this->isRecall() (which is a getter for '$this->recall'), but there was no
concomitant change to ensure that recall is set true on cache hits.

My fix does not set recall to true. The style of "pass-by-attribute" is tricky
and should be factored out by a subsequent change. This change moves the call
to writeCache() so that it is only called on cache miss.

Change-Id: I9b690e55001859c97fd40330272791d49ec6de75
Localisation updates from http://translatewiki.net.

Change-Id: I209506266dfee0d80e213c1542130e6b81e00399
Introduction of debugfeatures

* Introduce $wgDebugMath;
** If set to true additional fields in the database are created
** Especially the TeX code is store to have a change to asociate the database entries to the math content
* Testcase for the abstract MathRender class.
* Testcase for database access.
* Improvement of MathRenderer
** the chached values are written to the database with delay
** renaming of methods
* bugfix: in MathTexcv writeCache() I9b690e55001859c97fd40330272791d49ec6de75
** introduction of getters and setters
** check if values were changed and only write to cache in that case

Change-Id: Ic9e8ee7558e0496e3cffd4d3e8bea7a4c0c7d276
Specialpage MathDebug

This commit introduces the specialpage mathdebug. This page tests the rendering of typical math-expression using different rendering engines.
It is accessible if wgDebugMath is set to true for users with sysadmin rights.

Change-Id: I39f853a5a2a1a5dabdd0350b11b4ed3c0fe17ef8
Merge branch 'LaTeXML' of ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/Math into LaTeXML