Support for the IEEEeqnarray and IEEEeqnarray* environments

Is your feature request related to a problem? Please describe.
One of the professors in my department makes heavy use of the IEEEtran package in his works, specifically because he prefers using the IEEEeqnarray and 'd environments for more control over his layouts than align provides.

Describe the solution you'd like
Include support for the layouts of the IEEEeqnarray and IEEEeqnarray* environments.

Describe alternatives you've considered
Although align* is functionally similar, his preference is to be able to multiple aligned pieces that IEEEeqnarray provides. I told him I'd ask if here if it would be useful

Additional context
Minimal working document:

\documentclass{article}
\usepackage{IEEEtrantools}
\begin{document}

\begin{IEEEeqnarray*}{rCcCl}
  a& \le & b & \le & c \\
  d &\le & e &\equiv & f
\end{IEEEeqnarray*}

\end{document}

renders:

nicely aligned with each &.

Start by reproducing the minimal IEEEeqnarray* document from the issue and compare it with the existing align and align* behavior. Trace how MathJax recognizes and lays out aligned environments; done means both IEEEeqnarray and IEEEeqnarray* render the requested multiple aligned pieces and match the shown alignment.