remove spirit::multi_pass - refs #2397
Merge pull request #2400 from mapnik/single-pass-json

Drop multi_pass iterator
remove redundant private copy assignment op
fix compiler warning
Merge pull request #2403 from mapycz/3.x-fix-vertext_last-warning

fix compiler warning
Merge branch 'master' of https://github.com/mapnik/mapnik into 3x-msvs
Avoid boost auto-link warnings