correct signed/unsigned comparison in image filter visitor
Only call function if it is actually built.
Fix reference to non-existent 'colors'

Allows builds with DEBUG=true to succeed.
Merge pull request #2040 from mojodna/fix-debug-build

Fix debug build in 2.3.x
iwyu
merge with remote 2.3.x
respect args passed to apply_to_layer which repairs broken mapnik::request usage (#1737) after 7495d2f38141c
remove dead code
fix text related test failures on ubuntu precise/g++-4.7 - refs #2049
apply bbox clipping fix to shield symbolizer as applied to text in 96fff72837ec2fde - refs #2049
datasource_cache: display correctly the error message
backport ecf8c209380f from master
fix indent
Merge branch '2.3.x' of github.com:mapnik/mapnik