testcase for #983 against 2.3.x
fix collsion box for shields when scale_factor is used #2381
visual tests: don't exit without reporting
update expected visual images after fix for #2381
fix avoid-edges support for shields - closes #983
Merge branch '2.3.x' of github.com:mapnik/mapnik into gyp
fix compile with boost 1.56 - refs #2368
avoid warning from boost geometry
Merge branch '2.3.x' of github.com:mapnik/mapnik into gyp