Merge branch 'develop' into feature/platformio-30

* develop:
  Update docs for Teensy USB Features // Issue #722
  Implement Teensy 2.0 USB functionality (HID, SERIAL_HID, DISK, MIDI, etc.) // Resolve #722
  Add support for Pinoccio Scout board // Resolve #52
  Fix broken LD Script for Element14 chipKIT Pi board // Resolve #725  Resolve #726
  Fix USB flags processing for teensy platform // Issue #722
  Add Pinoccio board // Issue #52
  Minor improvements for CLion docs
  Improved docs for integration with CLion IDE
  Version bump to 2.11.1 (issues #472, #629, #710, #711, #712, #713, #718)
  Typo fix
  Add "udev" rules for OpenOCD CMSIS-DAP adapters // Resolve #718
  Update history
  Ignore "[platformio]" section from custom project configuration CI
  Bump to 2.11.1b1
  Add Arduino M0 Pro and Tian to the examples // Issue #472
  Fix issue when `pioenvs` folder doesn't exist
  Add more info about `.pioenvs` directory
  Improve CMSIS selection for SAMD21 boards
  Improve support for SAMD21 based boards
  Add contributing guidelines

platformio/util.py

@@ -220,10 +220,20 @@ def get_projectlib_dir():
 
 
 def get_pioenvs_dir():
-    return _get_projconf_option_dir(
+    path = _get_projconf_option_dir(
         "envs_dir",
         join(get_project_dir(), ".pioenvs")
     )
+    if not isdir(path):
+        os.makedirs(path)
+    dontmod_path = join(path, "do-not-modify-files-here.url")
+    if not isfile(dontmod_path):
+        with open(dontmod_path, "w") as fp:
+            fp.write("""
+[InternetShortcut]
+URL=http://docs.platformio.org/en/latest/projectconf.html#envs-dir
+""")
+    return path
 
 
 def get_projectdata_dir():