Add tests for issue #883
Resolve issue #883
Correctly display OpenCSG version for test suite
cgal vs. nocgal build tweaks
Split info() function into separate file as it depends on too many defines and external libs
add --autocenter option to make it easier to test 2d objects properly

Conflicts:
	src/Camera.cc
	tests/CMakeLists.txt
redo 2d tests to be viewed from the top down. experiment w altering viewall code

Conflicts:
	src/Camera.cc
	tests/CMakeLists.txt
	tests/regression/cgalpngtest/resize-2d-tests-expected.png
	tests/regression/cgalpngtest/rotate_extrude_dxf-tests-expected.png
	tests/regression/cgalpngtest/text-font-alignment-tests-expected.png
	tests/regression/cgalpngtest/text-font-direction-tests-expected.png
	tests/regression/cgalpngtest/text-font-simple-tests-expected.png
	tests/regression/cgalpngtest/text-font-tests-expected.png
	tests/regression/dumptest/resize-2d-tests-expected.csg
	tests/regression/opencsgtest/intersection2-tests-expected.png
	tests/regression/opencsgtest/resize-2d-tests-expected.png
	tests/regression/opencsgtest/rotate_extrude_dxf-tests-expected.png
	tests/regression/opencsgtest/text-font-alignment-tests-expected.png
	tests/regression/opencsgtest/text-font-direction-tests-expected.png
	tests/regression/opencsgtest/text-font-simple-tests-expected.png
	tests/regression/opencsgtest/text-font-tests-expected.png
	tests/regression/throwntogethertest/resize-2d-tests-expected.png
	tests/regression/throwntogethertest/rotate_extrude_dxf-tests-expected.png
	tests/regression/throwntogethertest/text-font-alignment-tests-expected.png
	tests/regression/throwntogethertest/text-font-direction-tests-expected.png
	tests/regression/throwntogethertest/text-font-simple-tests-expected.png
	tests/regression/throwntogethertest/text-font-tests-expected.png
Removed debug info
make default render like it was before. (bbox.center=center)
Fixed failing tests by adjusting some mistakes done while cherry-picking from the test_3d_export branch
allow alternate image comparison tool diffpng based on Hector Yee's algorithm

Conflicts:
	tests/CMakeLists.txt
	tests/test_cmdline_tool.py
test ImageMagick to see if two non-identical images are considered identical.
on failure, fall back to diffpng comparison (diffpng.cpp)
fix bug in imagemagick comparison detector
fallback to diffpng if ImageMagick is missing
allow alternate image comparison tool diffpng based on Hector Yee's algorithm

Conflicts:
	tests/CMakeLists.txt
update diffpng

Conflicts:
	tests/CMakeLists.txt
update diffpng.cpp
add test imgs for offpngtest and stlpngtest. updates to test_cmd and test_pretty_print
to handle missing expected images better and properly report img comparer.
tweak diffpng

Conflicts:
	src/OGL_helper.h
	tests/CMakeLists.txt
	tests/test_3d_export.py
	tests/test_cmdline_tool.py
	tests/test_pretty_print.py
tweak improvements for test pretty print logging. new intersection test img files

Conflicts:
	tests/regression/opencsgtest/intersection2-tests-expected.png
	tests/test_pretty_print.py
debugging messages. update diffpng

Conflicts:
	src/Camera.cc
	tests/CMakeLists.txt