add final/override keyword where possible to help compiler de-virtualize function calls
adding protobuf compiler to dependencies, used in branches
install protoc thru nuget
Merge pull request #1164 from Project-OSRM/appveyor_nuget

Install protoc on both Travis and AppVeyor.
first round of replacing deprecated typedefs with much nicer using statements
rename contra_flow to travel_mode, use unsigned char
add failing tests for travel mode
first cut at porting travel mode, some tests fail
most tests passing
use 4 bits for travel mode
improve tests for travel mode
fixes
more tests passing
fix initialization order to avoid compiler warning
remove spurious comment
remove unneeded methods
remove comment
reactivate assert of sizeof(NodeBasedEdgeData)
profile fixes
fix compilation of tests