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.
added final section of tutorial
capitalization off for subsections
Merge pull request #92 from JudsonWilson/judsons_examples

Judsons examples
minor fixes
made direct method default for SCS
added sum_squares to functions table
fixed typo in readme
added citing page
misspelled bibtex