Merge pull request #259 from chrox/master

update koreader-base
add a UTF8 character iterator

this speeds up font rendering since LuaJIT doesn't have to use
the interpreter for string.gsub(), which was used before
fixed bugs in implementation of utf8Chars()
Merge pull request #261 from hwhw/master

add a UTF8 character iterator
Merge pull request #260 from chrox/master

update k2pdfopt to version 2.00
update koreader-base for blitbuffer and ft ffi modules
Merge pull request #263 from houqp/houqp-master

update koreader-base for blitbuffer and ft ffi modules
update koreader-base to include fixes
Merge pull request #267 from hwhw/master

update koreader-base to include fixes
update koreader-base to include new djvulibre repo address