Factored out C/C++ API to submodule koreader-base
some adaptions to factored out C/C++ API
generate git-rev on package build
updated submodule koreader-base
updated koreader-base submodule to its new URI
Merge pull request #822 from houqp/make-fix

generate git-rev on package build
updated kindlepdfviewer repo location
Merge pull request #823 from hwhw/master

update repository location in a few places