ProcessorBase::selectPack() removed KF

Addressing #180 (closed): When a KF is removed after being notified to all the processors by keyFrameCallback(), the PackKeyFrameBuffer::selectPack...() functions can provide a KF pack which is being removed (it has no StateBlocks and is unlinked from the tree).

Since the decentralized structure of the KF callbacks, handling this within FrameBase::remove() is quite complicated. I rather add a check in the selectPack() and selectPackBefore() functions. They are called by the processors to get the notified KF since the last process().

Appliying #163 (closed): Changed the implementation and the name of the function selectPackBefore() (see issue for more info).

• All tests OK

• Merging to devel

src/test/gtest_pack_KF_buffer.cpp

@@ -144,7 +144,7 @@ TEST_F(BufferPackKeyFrameTest, selectPack)
     }
 }
 
-TEST_F(BufferPackKeyFrameTest, selectPackBefore)
+TEST_F(BufferPackKeyFrameTest, selectFirstPackBefore)
 {
     pack_kf_buffer.clear();
 
@@ -194,7 +194,7 @@ TEST_F(BufferPackKeyFrameTest, selectPackBefore)
         int j = 0;
         for (auto ts : q_ts)
         {
-            packQ = pack_kf_buffer.selectPackBefore(ts, tt);
+            packQ = pack_kf_buffer.selectFirstPackBefore(ts, tt);
             if (packQ)
                 res(i,j) = packQ->key_frame->getTimeStamp().get();