Always initialize members

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Mark parameters as const

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Fixed issue #2180: When opening revision graph, scroll to current branch

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Fix assertion of commit 7a366be49296acfeb841a199ebb09785552f1c9d

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>