pass optional by const ref
iwyu
refactor svg parsing so that libxml is not needed in the hpp file
avoid direct freetype usage in core/public hpp file so that mapnik C++ depedencies do no need to known the freetype include paths
fix compile of rasterlite plugin
Merge pull request #1756 from mapnik/isolate-freetype

Isolate freetype headers
remove workspace file from versioning
fix compile with python >=3
add the python libpath to ensure proper linking
round floating point to int - refs #1672
removed unused trunc and cmath headers - closes #1646
remove old versioning strings
clipping test - we do not expect a close path if using line clipper
Added new mapnik-config options: git-describe, defines, includes, dep-includes, and cxxflags - closes #1443
iwyu: mapnik::attribute
Merge pull request #1761 from avlee/issue1702

iwyu: mapnik::attribute
+ make benchmark tests copyable and avoid sharing state between threads
+ add polygon_clipper test
+ remove unused local vars
+ poss args by const ref
+ make operator=() non-throw
+ use std::swap()