`?!debug` and `?!nocache` inverted

`?!debug` and `?!nocache` URL parameter inverted in "Running PieCrust" page
Fix links in "Enabling pretty URLs" page
Merge pull request #2 from gerundt/patch-2

Fix links in "Enabling pretty URLs" page
Merge pull request #1 from gerundt/patch-1

`?!debug` and `?!nocache` inverted