support for retina and darcula images

(cherry picked from commit 48b5cc758d84ae22a99717a110ac2d33e6a2c48e)
update annotations tips

(cherry picked from commit 96c7ada90c792070bf3dcf87534a4d4aaccbff01)
update camel completion tips

(cherry picked from commit 4bc25fc9d540102fd7682ebe48c3b4359153d96d)
update camel case in goto tips

(cherry picked from commit 1c1ae34691d7bc03b29762ee7074c07808c2a430)
update tips resources

(cherry picked from commit ec424bc7d40d2e1b38044bc42f25ffcb5cdda742)
IDEA-116431 IntelliJ laf: menu shortcuts are invisible

(cherry picked from commit 2be66dbad956059796cf9939dd069d392bc8da5d)
IDEA-116445 IntelliJ laf: Menu bar is hardly visible on Linux

(cherry picked from commit f8981f953fc0ee5b8fb85c13e481193d3c41d730)
InspectionDescriptionNotFoundInspection -> ERROR level