Changes:
* LeafNode is aligned to LEAF_PAGE_SIZE.
Alignment brings 24 bytes memory overhead for 4096, but reduces
cache misses rate.
* Unused m_element_count from leaf nodes file.
The size is computed as m_leaves_region.size() / LEAF_PAGE_SIZE.
* Added try/catch for mmap exceptions messages.
Small fixes I didn't want to include in unrelated PRs.
There are a few left in `storage.cpp` but since it's a single function
in 600 lines of code, I didn't want to touch the mess. The others are
safe to remove, cucumber and test run on Finland gives 👍.
rather than being cached in the StaticRTree. This means we
can freely apply traffic data and not have stale values lying
around. It reduces the size of the RTree on disk, at the expense
of some additional data in RAM.
Fixes issue #1864. Given the simple set-up:
a --> b --> c
^-----------|
This would translate into an edge based graph (ab) -> (bc),
(bc) -> (ca), (ca) -> (ab).
Starting at the end of the one-way street (ab) and going to
the beginning, the query has to find a self-loop within the
graph (ab) -> (bc) -> (ca) -> (ab), as both nodes map to the
same segment (ab).
