Initial experimental import of MathJax source into Math extension as a client-side rendering supplement to the PNG rendering.

* Pulled in MathJax 1.1 (minus the 112 megabytes of PNG "fonts")
* Pulled in some of <https://en.wikipedia.org/wiki/User:Nageh/mathJax> bits for initialization

This doesn't currently override PNG images, but does replace the text-form if you configure it.
Straight update of MathJax to 2.0 -- doesn't currently load correctly if experimental $wgMathUseMathJax is enabled, be warned!

Using the unpacked files; minus the PNG fonts.
Tweak MathJax loading per recommendations from mathjax-users list:
* drop some of the init lines that don't appear to work/be needed
* only load MathJax.js through ResourceLoader; let MathJax's loader handle the rest

This gets us working in Chrome, where previously we hadn't initialized correctly. Should also help in IE, still needs testing.
Will probably want to swap in the pre-minimized versions of the files at some point, but the expanded ones are fine at this stage of work.
MathJax loading fixes from mathjax-users list:
* fix for $ stripping in IE
* wrap everything in {} for \displaystyle
tweaks to MathJax setup & customizations from mathjax-users list

Some fixes, cleanup, and modernization
use pre-minified MathJax files, they load faster
followup r113661 - fix for renamed func
Adding the tex colors to our texvc configuration, Fixes the lacking colors as pointed out in bug 35186.

We can remove the pre mathjax 2.0 color hack now that the color extensions is enabled.

Change-Id: I7863e3131689b2140e31cd09a3d663113f686b83
Adding arccot, arcsec and arccsc for bug 35186.

This says to treat these commands as Named functions, just as arcsin, arctan etc.

Change-Id: Ib11d9cb99f4ced0a063fd0913b9cacf544049f36
Load the TeX extension cancel, because it is supported by texvc and in use on wiki. Fixes part of Bug 35186

Change-Id: Icfb2894e4f755ae364a29bcace3e1d14b52c9e87
Merge "Adding arccot, arcsec and arccsc for bug 35186."
Remove textcolor macro. It was just a hack to make the colors work.

Change-Id: Ifbb05f3750075cbb4104bba5d1ef865fee8857e5
"\displaystyle" does not need curly braces as it does not take a parameter.

Thanks to User:Nageh for providing feedback:
https://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Mathematics/Archive/2012/Mar#mathJax_progress

Change-Id: I52781773c7146f87a839720867a49f1dd6d74483
Merge "Remove textcolor macro. It was just a hack to make the colors work."
Disable dangerous \href and \style commands

MathJax's TeX input by default includes \href and \style commands, which can be
used to inject JavaScript and web bugs. Disabling them by overriding them with
named function macros.

Change-Id: Id21253e9d1621b5ec4e93e28361c498c484b1b7b
(bug 35556) Allow MathJax to report errors.

Change-Id: Ibed05d3a4a28f7f99bc379f765d633256a8ddc12
(bug 36855) escape literal % in tex input

This removes support for MathML % comments, just as with texvc

PS2: Fix for regex lookbehind issue

Change-Id: I0cb026d749733ed3dbba8faacb163be4438fc6bb
Merge "(bug 36855) escape literal % in tex input"
(bug 35188) Do not poison the tex formula with markup

We move the block/inline styling (aka display vs textstyle) markup into
a filter used just before rendering. This way the 'used' formula will
not suddenly contain styling information that wasn't part of the
original formula.

Change-Id: Ie0c308c31d38581e556dc73109879c7a3d365121
Merge "(bug 35188) Do not poison the tex formula with markup"