merge libmaple docs ("leaflabs-docs") into ./docs

In the past, libample documentation was forked out of this repository
because the documentation had increased in scope. For the librambutan,
and the rambutan project in general, we will try to keep documentation
closer to the source code, so the librambutan-specific documentation
should live here. Other sections of leaflabs-docs will be culled in a
following commit.

This merge attempts to maintain history by using a subtree strategy.
Followed directions at:

    http://nuclearsquid.com/writings/subtree-merging-and-you/

Full history for files should be accessible using the "--follow" flag to
git log, eg:

    git log --follow docs/source/adc.rst

It should be possible to pull patches from leaflabs-docs with:

    git pull -s subtree leaflabs-docs master

... at least until the docs in this repository diverge significantly.

1 files changed, 55 insertions, 0 deletions

diff --git a/docs/source/lang/api/highbyte.rst b/docs/source/lang/api/highbyte.rst
new file mode 100644
index 0000000..4cb6f9b
--- /dev/null
+++ b/docs/source/lang/api/highbyte.rst
@@ -0,0 +1,55 @@
+.. highlight:: cpp
+
+.. _lang-highbyte:
+
+highByte()
+==========
+
+(Macro) Extracts the second lowest byte of an integral data type.
+
+.. warning:: This macro is provided for compatibility with Arduino
+   only.  It returns the second-least significant byte in an integral
+   value.  It makes sense to call this the "high" byte on a 16-bit
+   ``int`` microcontroller like the Atmel chips on Arduinos, but it
+   makes no sense at all on a 32-bit microcontroller like the STM32s
+   in the Maple line.
+
+   In short: we provide this so that existing Arduino code works as
+   expected, but **strongly discourage its use** in new programs.
+
+Syntax
+------
+
+::
+
+  highByte(x)
+
+Parameters
+----------
+
+**x**: a value of any integral type.
+
+Returns
+-------
+
+Second lowest byte in **x**.
+
+Example
+-------
+
+::
+
+    int x = 0xDEADBEEF;
+    SerialUSB.println(x, HEX); // prints "BE"
+
+Arduino Compatibility
+---------------------
+
+The Maple version of ``highByte()`` is compatible with Arduino.
+
+See Also
+--------
+
+-  :ref:`lowByte() <lang-lowbyte>`
+
+.. include:: /arduino-cc-attribution.txt