Merge pull request #78 from chrox/kctx_fix

bugfix: fix occasional reader crash when change screen mode from landscape to portrait in reflow mode
fix: set ReaderView.view_mode instead of ReaderUi.view_mode
credoc fix: load metadata info after document is rendered
enable scroll using pan gesture in readerrolling
readme update from Lucas Malor @ mobileread

see http://www.mobileread.com/forums/showpost.php?p=2488740&postcount=979
add back emulator screen setting hint
add nightlybuild script reference
Merge pull request #80 from houqp/readme-fix

readme update from Lucas Malor @ mobileread
Merge pull request #79 from houqp/houqp-master

enable scroll for readerrolling
update koreader-base: add top and bottom margin in reflowed page