Add example notebook sparse_solution from CVX.

This example was ported from the CVX example "Computing a sparse
solution of a set of linear inequalities" by Almir Mutapcic, 02/28/06.

Porting was done by Judson Wilson, 05/11/2014.

Overall, changes were minimal, and consisted mainly of formatting
changes to text and mostly straight porting code.
Add example notebook ant_array_min_beamwidth from CVX.

This example was ported from the CVX example "Minimize beamwidth of an
array with arbitrary 2-D geometry" by Almir Mutapcic, 02/02/06.

Porting was done by Judson Wilson, 05/14/2014.

Overall, code is very similiar, almost a straight port. Introductory
text has been heavility modified from the original author's version
to make the description match the code behavior.
Merge pull request #92 from JudsonWilson/judsons_examples

Judsons examples