Merge branch 'develop' into feature/platformio-30

* develop:
  Add support for ST Nucleo L031K6 board to ARM mbed framework
  Fix typo
  Fix pylint error
  Update history
  Improve linker flags handling for mbed
  Update examples
  Improve include selection for mbed boards with a custom vendor
  Re-submit a package to PyPI
  Version bump to 2.10.0 (issues #683, #687, #688, #689, #691)
  Pass PlatformIO macros with version to libs
  Update ARM mbed framework package to v121
  Typo fixes
  Move custom platform and board to separate page
  Add new ST Nucleo board
  Update build script for mbed framework
  Improve firmware uploading to Arduino Leonardo based boards // Resolve #691
  Typo fix

docs/platforms/creating_board.rst

@@ -11,8 +11,8 @@
 
 .. _board_creating:
 
-Custom Board
-============
+Custom Embedded Board
+=====================
 
 *PlatformIO* has pre-built settings for the most popular embedded boards. This
 list is available:

docs/platforms/creating_platform.rst

@@ -11,8 +11,8 @@
 
 .. _platform_creating:
 
-Custom Platform
-===============
+Custom Development Platform
+===========================
 
 *PlatformIO* was developed like a tool that may build the same source code
 for the different development platforms via single command :ref:`cmd_run`

docs/platforms/custom_platform_and_board.rst

@@ -0,0 +1,19 @@
+..  Copyright 2014-present Ivan Kravets <me@ikravets.com>
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+       http://www.apache.org/licenses/LICENSE-2.0
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+Custom Platform & Board
+=======================
+
+.. toctree::
+    :maxdepth: 2
+
+    creating_platform
+    creating_board