Adding template to be used with IEEETran.cls

The IEEETrans class can be found at

  http://www.michaelshell.org/tex/ieeetran/

The template modifies minimally the default latex template:

  * fixes the document class to `IEEETran`
  * uses custom `IEEEauthorblock*` commands for the authors section

The variables expected for the author metadata (in YAML format) are of
the form:

    title: 'A Title'
    author:
    - names: Student Foo, Advisor Bar
      affiliation: University of Foo
    - names: Other Collaborator
      affiliation: Collaboration Agency
    - names: A Third One
      affiliation: Coolest Place

The above assumes that at most three affiliations will be there. If not,
then the alternative format has to be used but that's not supported
currently.
Adding support on "default" template for YAML header

The convention for authors is:

---
  author:
     names:
     affilitaion:
     ...
---

same as for the IEEETran template
Adding template to be used with a0poster class

Basic stuff, will incorporate more configuration and document it better
later.