Added linear and agular deflection settings to STL codec

Author: jmwright

README.md

@@ -82,6 +82,10 @@ cat /input/path/script.py | cq-cli.py --codec step | wc -l
 ```
 ./cq-cli.py --codec svg --infile /input/path/script.py --outfile /output/path/newfile.svg --outputopts "width:100;height:100;marginLeft:12;marginTop:12;showAxes:False;projectionDir:(0.5,0.5,0.5);strokeWidth:0.25;strokeColor:(255,0,0);hiddenColor:(0,0,255);showHidden:True;"
 ```
+8. Convert a CadQuery script to STL, passing in output options to change the quality of the resulting STL. Explanation of linear vs angular deflection can be found [here](https://dev.opencascade.org/doc/occt-7.1.0/overview/html/occt_user_guides__modeling_algos.html#occt_modalg_11_2).
+```
+./cq-cli.py --codec stl --infile /input/path/script.py --outfile /input/path/script.stl --outputopts "linearDeflection:0.3;angularDeflection:0.3"
+```
 
 ## Drawbacks
 

cqcodecs/cq_codec_stl.py

@@ -8,10 +8,19 @@ def convert(build_result, output_file=None, error_file=None, output_opts=None):
     temp_dir = tempfile.gettempdir()
     temp_file = os.path.join(temp_dir, "temp_stl.stl")
 
+    linearDeflection = 0.1
+    angularDeflection = 0.1
+
+    # If the user has provided the deflection settings, use them
+    if "linearDeflection" in output_opts:
+        linearDeflection = output_opts["linearDeflection"]
+    if "angularDeflection" in output_opts:
+        angularDeflection = output_opts["angularDeflection"]
+
     # The exporters will add extra output that we do not want, so suppress it
     with helpers.suppress_stdout_stderr():
         # Put the STEP output into the temp file
-        exporters.export(build_result.results[0].shape, temp_file, exporters.ExportTypes.STL)
+        exporters.export(build_result.results[0].shape, temp_file, exporters.ExportTypes.STL, tolerance=linearDeflection, angularTolerance=angularDeflection)
 
     # Read the STEP output back in
     with open(temp_file, 'r') as file: