Moved DXF export scripts to separate directory.
Extracted common functions to separate module.
Added support for recording dependencies while compiling OpenSCAD files.
Added more example files to showcase dependency tracking.
Merge branch 'master' into no-examples
Revert "Added more example files to showcase dependency tracking."

This reverts commit b69003800917a93c5c2b240ede6f83b80f1095cc.