Contractor: log stats for loaded speed files

[freenerd]

Fixes #2434

Output looks like this:

[info] Opening /tmp/extract.osrm.ebg
[info] Reading 702 edges from the edge based graph
[info] Loaded speed file /tmp/speeds.csv with 2 speeds
[info] In total loaded 1 speed file(s) with a total of 2 unique values
[info] Used 3382 speeds from LUA profile or input map
[info] Used 2 speeds from /tmp/speeds.csv

Todo:

• Figure out what the high number in speeds from LUA profile means (one way streets are a thing)
• Code review

[TheMarex]

@freenerd build is failing on travis. Seems like you forgot to include atomic somewhere.

[daniel-j-h]

For the record: https://gcc.gnu.org/ml/libstdc++/2015-01/msg00121.html
We need to workaround GCC 4.8's libstdc++ not defining atomic_init.

[daniel-j-h]

@freenerd if you want to use relaxed memory orders:
08f3a0b#diff-5d25f965a92c5af3a4dfd03cf4f7616aR501
then it would make sense to fetch_add for incrementing the counters with relaxed instead of += 1:
http://en.cppreference.com/w/cpp/atomic/atomic/fetch_add

[freenerd]

@daniel-j-h using std::memory_order_seq_cst which should work okay?

[daniel-j-h]

store(0); for initialization is good enough, as store has sequential consistency as default second argument already: http://en.cppreference.com/w/cpp/atomic/atomic/store