create new pdfellipse object for drawing ellipses (and circles). Refactor PDFLine, PDFRectangle, and PDFEllipse into a PDFDraw base class.
add other files affected by the change
Correct use of PDFCell using PDFRectangle for generating filled
rectangles.
Revert "Fixed runexamples"

This reverts commit 0da480d804417da85c47f83c80089f7058f6bba7.
Merge pull request #6 from tjoneslo/master

Add PDFEllipse to draw circles and ellipses