SQL refactor (#160)

* Remove Contest and DataFrame traits, just use SqlContext and SqlDataFrame directly
* Update sqlgen and use dialect constructors
* Add std::fmt::Error to VegaFusionError
* Move query-to-string generation out of connection. This way the SqlDataFrame can check whether a query is supported by the connection's dialect on its own.
* Add sqlgen parser error type to VegaFusionError

.github/workflows/build_test.yml

@@ -34,7 +34,7 @@ jobs:
         os:
          - ubuntu-latest
          - windows-2022
-         - macos-10.15
+         - macos-11
 
     steps:
       - name: Check out repository code
@@ -76,14 +76,21 @@ jobs:
         with:
           command: test
           args: --all-features --workspace --exclude vegafusion-python-embed --exclude vegafusion-wasm
+      - name: Upload test artifacts
+        uses: actions/upload-artifact@v2
+        if: always()
+        with:
+          name: vegafusion-rt-test-images
+          path: |
+            vegafusion-rt-datafusion/tests/output
 
   build-vegafusion-server:
     strategy:
       matrix:
         options: [
             [ubuntu-latest,  linux-64],
             [windows-2022,  win-64],
-            [macos-10.15,   osx-64],
+            [macos-11,   osx-64],
         ]
     runs-on: ${{ matrix.options[0] }}
     steps:
@@ -302,7 +309,7 @@ jobs:
             [ubuntu-latest,  linux-64, "bash -l {0}",  manylinux2014_x86_64, cp310],
 # TODO: Should run tests on Windows and Mac as well, but there a GitHub action issues
 #            [windows-2019,  win-64,   "pwsh",         win_amd64,            cp37],
-#            [macos-10.15,   osx-64,   "bash -l {0}",  macosx_10_7_x86_64,   cp37],
+#            [macos-11,   osx-64,   "bash -l {0}",  macosx_10_7_x86_64,   cp37],
         ]
     runs-on: ${{ matrix.options[0] }}
     defaults:

.gitignore

@@ -36,3 +36,4 @@ _vegafusion_data
 /javascript/vegafusion-embed/package/css/
 /javascript/vegafusion-embed/package/lib/
 /vegafusion-server/examples/chart_editor/node_modules/
+/vegafusion-rt-datafusion/tests/data/