Merge pull request 'Build assimp from sources every time for correct linkage after regenerating solution' (#172) from misc into master

Reviewed-on: https://git.madvoxel.net/OpenVulkano/OpenVulkano/pulls/172
Reviewed-by: Georg Hagen <georg.hagen@madvoxel.com>

3rdParty/assimp/CMakeLists.txt

@@ -7,7 +7,7 @@ if (NOT IOS)
 endif ()
 if (assimp_FOUND OR ASSIMP_FOUND)
     message("Using system assimp")
-elseif (ENABLE_ASSIMP AND NOT assimp_BUILT)
+elseif (ENABLE_ASSIMP)
     message("Building assimp from sources")
     if(NOT DEFINED ASSIMP_REPO)
         set(ASSIMP_REPO https://github.com/assimp/assimp.git)