refactor marker placements
Merge pull request #2388 from mapycz/3.x-refactor-markers-placement

refactor marker placements
remove svg renderer test since its not actually asserting anything useful
remove svg renderer test
avoid warning from boost geometry

Conflicts:
	plugins/input/geojson/geojson_datasource.hpp
fix inialization order
remove duplicate calculation of image_ratio
expressions - implement unary and binary function expression nodes
(sample functions: exp, pow, sin, cos, min, max, tan, atan)
expressions - refactor function calls into separate compilation unit
expressions - add 'abs' function
ogr: also accept 'inline' arg like geojson/topojson/csv plugins
Add from_geojson test that validates current behavior - refs #2390
respect int return type for WebPValidateConfig
simplify expression handling in marker_helpers
add support for windows unicode paths in rapidxml loader

Conflicts:
	src/rapidxml_loader.cpp
Add visual test
fix gdal compile with msvs 2013 - closes #2257
expression_string : implement function call support
avoid creating expression_string(str) visitor objects recursively
implement unary functions as functors