Tests for EPS thumbnail bugfix

Here's tests for https://github.com/python-imaging/Pillow/pull/619

1. The two test .eps files are opened and **resized** to (100, 100). The size is then asserted as (100, 100). 
-> As expected, this test passes without the bugfix.

2. The two test .eps files are opened and **thumbnailed** to (100, 100). The size is then asserted as (100, 100). 
-> As expected, this test fails without the bugfix: https://travis-ci.org/hugovk/Pillow/builds/24691454

This also contains the other recent upstream changes (i.e. latest https://github.com/python-imaging/Pillow) since you forked.