backend_pgf: \pgftext now requires \color inside argument (fix #3779)
backend_pgf: Check text color in tests
Fix compiler warning
Merge pull request #3780 from pwuertz/fix_3779

BUG : backend_pgf: \pgftext now requires \color inside argument (fix #3779) [backport to 1.4.x]
Merge pull request #3781 from mdboom/compiler-warning

MNT : Fix compiler warning
Merge pull request #3777 from mdboom/upgrade-agg

MNT : Upgrade agg to SVN version
Use floating-point rendering buffer
More floating-point buffer progress