Issue #27: Lint stage

Signed-off-by: Felipe Shi Iu Wu <felipeshiwu@gmail.com>

.gitlab-ci.yml

 stages:
+    - lint
     - build
     - test
 
+pattern:
+    stage: lint
+    tags:
+        - regular
+        - debian
+    script:
+        - shopt -s extglob
+        - apt-get update && apt-get install -y git python
+        - git clone https://github.com/google/styleguide
+        - cd styleguide/cpplint
+        - ./cpplint.py --filter=-whitespace/blank_line,-build/include_what_you_use ../../src/!(jsoncpp).cpp  ../../src/linux/*.cpp ../../src/windows/*.cpp
+
 compile:
     stage: build
     artifacts:
@@ -13,7 +26,7 @@ compile:
         - debian
     script:
         - echo "Estágio 'build'"
-        - apt-get update && apt-get install -y build-essential cmake git 
+        - apt-get update && apt-get install -y build-essential cmake git
         - git submodule init
         - git submodule update --init --recursive
         - mkdir build