add yamllinter check (#124)

* add yamllinter check

* ignore validation.yml

* enhancement

* cleanup

extensions/lang-english/.travis.yml

@@ -0,0 +1,7 @@
+language: bash
+
+before_script:
+  - go get github.com/sijad/yaml-translation-utils/yamllinter
+
+script:
+  - bash scripts/linter.sh

extensions/lang-english/scripts/linter.sh

@@ -0,0 +1,32 @@
+if ! [ -x "$(command -v yamllinter)" ]; then
+  echo 'Error: yamllinter is not installed.' >&2
+  exit 1
+fi
+
+GREEN='\033[0;32m'
+RED='\033[0;31m'
+NC='\033[0m'
+
+cd "./locale"
+
+RC=0
+
+for r in *.yml
+do
+  [ "$r" != "validation.yml" ] || continue
+
+  echo "Checking $r:"
+
+  yamllinter --file "$r" --level 2
+
+  if [ $? -eq 1 ]; then
+    RC=1
+    printf "${RED}⨉ faild${NC}\n"
+  else
+    printf "${GREEN}✓ passed${NC}\n"
+  fi
+
+  echo
+done
+
+exit $RC