repair fab function.
Merge branch 'master' into RemoveNavigationDrawer
add umeng custom event. but "collect_delete_home" not yet(cannot delete from collection yet)
add collection no item hint view.
Merge branch 'master' into RemoveNavigationDrawer

Conflicts:
	app/src/main/kotlin/com/ybook/app/ui/MainActivity.kt
apply MVP for SearchActivity.
change the image of FAB.
small bug fixed.
change Umeng channel to pre release.
fix the previous commit.
handle with the situation when there is only one search result.
Merge branch 'master' into RemoveNavigationDrawer
fix issue: crash when only one search result.
Merge branch 'master' into RemoveNavigationDrawer
fix the about menu item.
update aboutView's contain.
update aboutView's contain.
Merge branch 'master' into RemoveNavigationDrawer

Conflicts:
	app/src/main/kotlin/com/ybook/app/ui/MainActivity.kt
	app/src/main/kotlin/com/ybook/app/ui/NavigationDrawerFragment.kt
merge from main branch.