switch to new dynamic loading library build

separate output directories are created per-architecture
small fixes
fix out-of-bound bug in filemanager
Merge pull request #217 from houqp/houqp-master

fix out-of-bound bug in filemanager
interim merge of latest upstream
consolidated Makefile, adapted to dynlib approach
update koreader-base submodule
Merge pull request #205 from hwhw/master

Adaptions for dynamic library aware koreader-base and some streamlining
transfer libk2pdfopt to koreader
Merge pull request #218 from chrox/master

transfer libk2pdfopt to koreader