Bump base for cre.cpp cleanup and utf8proc FFI.
Add a checkbutton for case sensitive search in FileBrowser,
and use Utf8Proc.lowercase() for case insensitive search.
Also use it in ReaderUserHyph as a replacement for
crengine getLowercasedWord().
The hyphenation of a word can be changed from its default
by long pressing for 3 seconds and selecting 'Hyphenate'.
These overrides are stored in a per-language file, i.e:
koreader/settings/user-German.hyph.
