Improve handling of PHP errors

This converts any error (including INFO, NOTICE and those hidden with @)
to an exception and displays a nice error page for uncaught exceptions.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
thumbnails: Handle EXIF orientation

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Update NEWS

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Add colorbox on thumnail pages

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Move thumbnail code to dedicated class

This also moves the code from mfile->image_dimension() to the only
place where it was called.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Rework image manipulation class

This is the first of hopefully more classes using namespaces and proper
classes that can be used as objects rather than CI's singleton
approach. The namespace is mainly used to gain nice autoloading
capabilities and it's not really yet used for separation.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Support EXIF orientation in colorbox

This also reindents colorbox.css.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Only use colorbox if it's loaded

Signed-off-by: Florian Pritz <bluewind@xinu.at>