update expected image after pixel snapping change
Travis: remove lto testing code
attempt to repair postgres install
travis: alt gdal approach
travis: another try at gdal
travis: debug postgis
travis: yet another try to keep postgis installed
travis: give up on gdal
fix compile with older OGR
travis: drop removal of postgis
remove unused (after grammar refactor) support_multi_pass.hpp include
update expected test after 41064ed49d
adapt to ptree change in boost 1.56 - closes #2365

Conflicts:
	src/save_map.cpp
fix #2368
adapt geojson+topojson plugins to boost 1.56 - refs #2367
fix compilation with boost < 1.56
GeoJSON : re-implement grammar to allow any order for "type", "coordinates" and "geometries" elements
Also, ammend positions parser to handle multi-dimensional coordinates e.g [x,y,z,....,N] (we only extract x and y)
topojson plugin : fix spatial index population, rename 'count' to 'index'
fix geojson plugin, even better name is geometry_index (to avoid confusion)
c++ pedantic