A couple of features and bug fixes

Hello there,
I have been testing out Lychee fixing bugs and adding minor features in progress. Here is a list of  the changes I have introduced so far. 

* Faster photo browsing thanks to caching.
* Default sort order of albums is changed from new to old.
* Preserves scroll position when changing from albums to album and vice versa
* Better Unicode support for values read from the database

Hopefully these are of use to you. If you have any questions, do not hesitate to ask.

Cheers,
Roman
Would be better to preload the next photo after the current photo has been loaded (it should have the higher priority). What do you think?