Using epstopdf LaTeX package

Instead of calling `epstopdf` from MATLAB, use the `epstopdf` package
in LaTeX. This package is a standard CTAN package that calls `epstopdf`
behind the scenes using a protected shell escape.

It might be necessary to add `--enable-write18` to your PDFLaTeX invokation.

However, on more recent versions of MacTex/TeXLive, everything should
work out of the box. Tested on MacTeX 2013 (OS X 10.9).