multimedia/assimp: Update to 4.1.0

Change log:
https://github.com/assimp/assimp/releases/tag/v4.1.0

Additional port changes:

• Removed CMAKE_SKIP_RPATH, the default behavior should suffice
• Changed to CMAKE_OFF
• Removed the unnecessary .if/gcc clause
• Improved PLIST_SUB tokens
• Added the patch for #include that is already in the upstream repository now

Also tried to add the double-precision option, but it fails in build,
so I reported this to the upsream.

Bumped PORTREVISION: games/pioneer games/doomsday graphics/qt5-3d

Submitted by: myself
Reported by: portscout
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D14253