Refactor code to new svgtex

* svgtex has improved a lot so the changes were adopted to mathoid
* mathoids extra features are designed in a way that they can be
  merged back to svgtex
* some features of mathoid were replaced by svgtex features

Thanks to Peter Krautzberger for the management of the communication
flow.

Change-Id: I2fe448aa97d2ffd2a3b18d1070819a3dc9fa2072