Fusion: Shutdown fixes, fix for blocking read() usage
Fusion: Shutdown fixes, fix for blocking read() usage

- Unlink shared root page file on shutdown
- Reimplement fusion_sync() via new FUSION_SYNC ioctl
- Handle EINTR in fusion_dispatch_loop() when read() returns

dfbdok/DirectFB1,Distrotech/DirectFB,DirectFB/directfb,djbclark/directfb-core-DirectFB,jcdubois/DirectFB,djbclark/directfb-core-DirectFB,Distrotech/DirectFB,kevleyski/DirectFB-1,deniskropp/DirectFB,kevleyski/directfb,kevleyski/DirectFB-1,kevleyski/DirectFB-1,kevleyski/directfb,Distrotech/DirectFB,deniskropp/DirectFB,lancebaiyouview/DirectFB,mtsekm/test,lancebaiyouview/DirectFB,dfbdok/DirectFB1,lancebaiyouview/DirectFB,kevleyski/DirectFB-1,mtsekm/test,dfbdok/DirectFB1,kaostao/directfb,kevleyski/directfb,DirectFB/directfb,djbclark/directfb-core-DirectFB,lancebaiyouview/DirectFB,sklnet/DirectFB,kaostao/directfb,jcdubois/DirectFB,kevleyski/directfb,mtsekm/test,sklnet/DirectFB,deniskropp/DirectFB,sklnet/DirectFB,sklnet/DirectFB,djbclark/directfb-core-DirectFB,kaostao/directfb,jcdubois/DirectFB,DirectFB/directfb,deniskropp/DirectFB