diff --git a/.clang-format b/.clang-format
index ffb2a92..9d355d6 100644
--- a/.clang-format
+++ b/.clang-format
@@ -20,6 +20,7 @@ BreakBeforeBraces: Custom
 BreakBeforeTernaryOperators: false
 ColumnLimit:     100
 ConstructorInitializerIndentWidth: 2
+IncludeBlocks: Preserve
 IncludeCategories:
 
   # Local includes "":
diff --git a/circle.yml b/circle.yml
index 2666da9..bc1c02b 100644
--- a/circle.yml
+++ b/circle.yml
@@ -56,7 +56,8 @@ commands:
 jobs:
 
   lint:
-    executor: linux
+    docker:
+      - image: ethereum/cpp-build-env:12-lint
     steps:
     - checkout
     - run:
@@ -68,7 +69,7 @@ jobs:
     - run:
         name: "Run codespell"
         command: |
-          codespell --quiet-level=4 --ignore-words=./.codespell-whitelist
+          codespell --quiet-level=4 --ignore-words=./.codespell-whitelist --skip=.git
     - run:
         name: "Check bumpversion"
         command: |
@@ -126,18 +127,14 @@ jobs:
       - build_and_test
 
   build-gcc6:
-    executor: linux
-    environment:
-      CC: gcc-6
-      CXX: g++-6
+    docker:
+      - image: ethereum/cpp-build-env:12-gcc-6
     steps:
       - build_and_test
 
   build-clang38:
-    executor: linux
-    environment:
-      CC: clang-3.8
-      CXX: clang++-3.8
+    docker:
+      - image: ethereum/cpp-build-env:12-clang-3.8
     steps:
       - build_and_test
 
diff --git a/examples/example_vm/example_vm.c b/examples/example_vm/example_vm.c
index 5bde510..085ca48 100644
--- a/examples/example_vm/example_vm.c
+++ b/examples/example_vm/example_vm.c
@@ -8,7 +8,7 @@
 ///
 /// This VM does not do anything useful except for showing
 /// how EVMC VM API should be implemented.
-/// The inplementation is done in C only, but could be done in C++ in very
+/// The implementation is done in C only, but could be done in C++ in very
 /// similar way.
 
 #include "example_vm.h"