use pyproject.toml for tooling, add isort

script/coverage

@@ -38,8 +38,6 @@ grep -r -I --line-number "# pragma: +no.*cover" $SOURCE_DIR && {
     exit 1
 }
 
-export PYTHONPATH=.:$PYTHONPATH
-
 pytest \
   --disable-network \
   --cov-reset \

script/format

@@ -6,4 +6,5 @@ SOURCES=$(find *.py octodns tests -name "*.py")
 
 . env/bin/activate
 
-black --line-length=80 --skip-string-normalization --skip-magic-trailing-comma "$@" $SOURCES
+isort "$@" $SOURCES
+black "$@" $SOURCES

script/test

@@ -30,6 +30,4 @@ export ARM_CLIENT_SECRET=
 export ARM_TENANT_ID=
 export ARM_SUBSCRIPTION_ID=
 
-export PYTHONPATH=.:$PYTHONPATH
-
 pytest --disable-network "$@"