Add basic lint travis check

.gitattributes

@@ -0,0 +1,8 @@
+*     text eol=lf
+
+*.ico binary
+*.jpg binary
+*.png binary
+*.zip binary
+*.mp3 binary
+*.gif binary

.travis.yml

@@ -9,6 +9,7 @@ cache:
     - "$TRAVIS_BUILD_DIR/.piolibdeps"
 
 script:
+  - python travis.py
   - platformio run -e $BUILD_TARGET
 
 matrix:

travis.py

@@ -0,0 +1,46 @@
+from __future__ import print_function
+import glob
+import sys
+import codecs
+import os.path
+
+errors = []
+
+
+def find_all(a_str, sub):
+    for i, line in enumerate(a_str.splitlines()):
+        column = 0
+        while True:
+            column = line.find(sub, column)
+            if column == -1:
+                break
+            yield i, column
+            column += len(sub)
+
+
+files = []
+for root, _, fs in os.walk('src'):
+    for f in fs:
+        _, ext = os.path.splitext(f)
+        if ext in ('.h', '.c', '.cpp', '.tcc'):
+            files.append(os.path.join(root, f))
+files.sort()
+
+for f in files:
+    try:
+        with codecs.open(f, 'r', encoding='utf-8') as f_handle:
+            content = f_handle.read()
+    except UnicodeDecodeError:
+        errors.append("File {} is not readable as UTF-8. Please set your editor to UTF-8 mode."
+                      "".format(f))
+    for line, col in find_all(content, '\t'):
+        errors.append("File {} contains tab character on line {}:{}. "
+                      "Please convert tabs to spaces.".format(f, line, col))
+    for line, col in find_all(content, '\r'):
+        errors.append("File {} contains windows newline on line {}:{}. "
+                      "Please set your editor to unix newline mode.".format(f, line, col))
+
+for error in errors:
+    print(error)
+
+sys.exit(len(errors))