IMPORT: read SAT, STEP, IGES and WMF files; ACISIN and WMFIN

ACIS text files come in one object per body (3DSOLID, REGION or SURFACE).
STEP B-rep models become a block per product with component inserts at
their placements, scaled to the drawing's units; IGES manifold solids come
in as 3DSOLIDs scaled to the drawing's units with their colours. Splines
that are exactly analytic shapes are kept as those shapes. Windows
metafiles become a WMF<n> block of polylines and text fitted to half the
view, placed at its top-left corner or by WMFIN's insertion prompts. The
Import File window lists the four formats as supported.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.toml

@@ -222,3 +222,10 @@ harness = false
 [[test]]
 name = "integration"
 path = "tests/integration.rs"
+
+[patch."https://github.com/HakanSeven12/opencadcodec.git"]
+opencadcodec = { git = "https://github.com/ramox81/cadcodec.git", rev = "6c33e24" }
+
+[patch."https://github.com/HakanSeven12/opencadkernel.git"]
+opencadkernel = { git = "https://github.com/ramox81/cadkernel.git", rev = "9490fb8" }
+opencadkernel-constraints = { git = "https://github.com/ramox81/cadkernel.git", rev = "9490fb8" }