First try of drag and drop
Add demo for double click
Fix add eventListener
Correct charcode
First operations of sum

Add operation of sum to some elements.

Add new demo for sum of elements.
Write documentation

Add lots of documentation for users and developers.

Some fix in the library.
Implement 3 user options

The effect of the global variables MATHCOLOR, ONLYDISPLAY and
MATHOVERWRITE are implemented.

Some demos of the options have been add.
Add MathML namespace

Replace document.createElementNS(...) with document.createElementNS(...)
and add the MathML namespace (http://www.w3.org/1998/Math/MathML).

Thanks to Frédéric Wang <fred.wang@free.fr>.
Fix examples that break in 5df0114

Some examples break because it use inline math. This have been
fixed using the `MATHOVERWRITE` and `ONLYDISPLAY` options.
Add meta charset in demos
Improve basic interaction

* Now a right click will ask for replace symbol and the double left
  click will bublle for symbols.
* Add function to replace InvisibleTimes.
* Add setDblclick when need.
* Fix bug in replaceMiByMn due unicode number.
* Fix bug in miDblclick due the return code.
* Fix bug in opPlusMiMi since setDblclick are missing.
* Add interaction for `-`.
* Add interaction for `*`.
* Add interaction for `/`.
* Add interaction for mfrac.
* Add interaction for mroot.
* Add interaction for msqrt.
* Update documentation.
* Add demos.
* Clean up the code.
Add limit for decimals

* Add limit for decimals so that operations (division and root)
  not show too much decimals (the default are only 2).
* User options are now attribute of a object named `MATHMLJS`.
* Update demos.
Create function mi2mn

* Create a function to convert mi elements into mn.
* Change localName to nodeName.
Add power function and others changes

* Add power function.
* Add function to remove mrow that is a negative number.
* Add function to restore negative number.
* Add function opSiblingHash and opChildHash.
* Fix bug in miContextmenu.
* Cleanup the code using mathmlSetupElement.

Note: Probably in the next commit the function to restore
negative number will be generalized to cleanup the code.
Add first github pages
Update proof of concept example.
Improve mathmlPreserve

Add heurist to avoid the operation in some cases.
Improve demos

* Improve the information in `doc/demos/index.html`.
* Add footer and address to all demos.
Add "undo" feature

* Add "undo" feature for display math.
* Add `toLowerCase()` method when request `nodeName`.
* Improve documentation.
Add note about browser support.