Update fontbox dependency

What has changed in fontbox

There are no major functionality changes in this update.

Fontbox adds the following bug-fixes:

Fixes missing documentation on Element and other objects which should have been documented.
The x and y fields in PageCursor are now private - they should have been originally. They can be read using x() and y(), or written using left(n) and top(n); they can be scrolled using pushLeft(n) and pushDown(n).
Removes some magic constants which float around during processing and layout which should have been externalized originally.
Fixes an issue where color images render purely in black (and white?). See AfterLifeLochie/fontbox#10
Temporarily fixes an issue where the parser can try and place words which cannot physically fit on the page. This is currently patched in pull AfterLifeLochie/fontbox#7 but a more permanent fix is pending.
Fixes an issue where custom lighting rendering could render images washed-out.