ignore sympy folder in run_format.sh (#343)

* ignore sympy folder in run_format.sh

The sympy folder contains generated cpp files which we don't want to
auto-format.

This was apparently missed during the py -> sympy folder rename:
4da9a55

See: #342 (comment)

* run_format.sh: fix header files not being formatted

run_format.sh

@@ -1 +1 @@
-find . -type d \( -path ./py -o -path ./doxyrest_b -o -path "./*/CMakeFiles/*" \) -prune -o  -iname *.hpp -o -iname *.cpp -print | xargs clang-format -i
+find . -type d \( -path ./sympy -o -path ./doxyrest_b -o -path "./*/CMakeFiles/*" \) -prune -o \( -iname "*.hpp" -o -iname "*.cpp" \) -print | xargs clang-format -i