change list<map> to list<Exhibition>
add attention in exhibition brief page
modify list<HashMap> to list<Exhibition>
OK
finish
change captureActivity to portrait
Revert "finish"

This reverts commit 97ebd72099b1a0d5962b016be0c35390b89a0cf5.
change scan page to portrait
modify qrcodeActivity when no attention
change attention to signup when you click attention button in exhibitionbrief page