Allow numbers starting with decimal in fast_atof.
Allow several spaces between numbers in OBJ files.
Cleanup CMakeLists for unit tests, drop unneeded Windows dependency.
Add StreamWriter utility (mostly symmetric to StreamReader).
assimp_view: fix crash when trying to export while no model is loaded.
Extend StreamWriter to write to a buffer and to allow re-positioning of the write cursor within the buffer.
Don't use isdigit() in fast_atof.
Don't use isspace() in OBJ file parser.
Add test OBJ containing various number formats.
Add test OBJ w/ multiple spaces between elements.
Merge pull request #316 from tgnottingham/master

Allow numbers starting with decimal in fast_atof. Allow several spaces between numbers in OBJ files.
Initial implementation of 3DS Exporter. Hierarchy exporting and smoothing groups missing.
Fix CI build.
3DS Export: fix texture export.
3DS Exporter: export scene hierarchy.
Merge pull request #317 from assimp/export-3ds

3DS Exporter
Add X and 3DS exporter to readme.