3.x port of localized font caching and then some
fix benchmark compile
c++ style
unique_ptr for font_face_set
ignore font cache in map assignment and comparison
cleanup
add code comments to create_face
simplify code in create_face
Merge branch 'master' of github.com:mapnik/mapnik into localized-font-cache

Conflicts:
	src/build.py
Merge branch 'master' of github.com:mapnik/mapnik into localized-font-cache
fix multiple attach to the same sqlite database
fix -Wdangling-else warning in clipper.cpp
fix visibility of agg headers needed for svg2png built with -fvisibility=hidden - similiar to #1860
Use a smaller input file for testing dataraster 16bsi

Also test a minor number of overviews.
The aim is to make the test faster (#2470)
Further speedup dataraster test by importing only tiled
Merge pull request #2477 from mapycz/fix-plugin-sqlite

fix multiple attach to the same sqlite database
c++ style
explicitly initialize all members of layer class in ctor
explicit move ctor for feature_type_style
fix layer buffer default