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, 68 insertions, 0 deletions

diff --git a/docs/source/lang/api/map.rst b/docs/source/lang/api/map.rst
new file mode 100644
index 0000000..69661a0
--- /dev/null
+++ b/docs/source/lang/api/map.rst
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+.. highlight:: cpp
+
+.. _lang-map:
+
+map()
+=====
+
+Re-maps a number from one range to another.
+
+.. contents:: Contents
+   :local:
+
+Library Documentation
+---------------------
+
+.. doxygenfunction:: map
+
+Discussion
+----------
+
+``map()`` does not constrain values to within the range, because
+out-of-range values are sometimes intended and useful. The
+:ref:`constrain() <lang-constrain>` macro may be used either before or
+after this function, if limits to the ranges are desired.
+
+Note that the "lower bounds" of either range may be larger or smaller
+than the "upper bounds" so that ``map()`` may be used to reverse a
+range of numbers; for example::
+
+    y = map(x, 1, 50, 50, 1);
+
+The function also handles negative numbers well, so that this
+example ::
+
+    y = map(x, 1, 50, 50, -100);
+
+is also valid.
+
+The ``map()`` function uses integer math (its arguments and return
+values all have type :ref:`long <lang-long>`), so it will not generate
+fractions, when the math might indicate that it should do so.
+Fractional remainders are truncated, and are not rounded or averaged.
+
+Example
+-------
+
+::
+
+    /* Map an ADC reading (12 bits) to 16-bit PWM (0 to 65,535) */
+
+    void setup() {
+        pinMode(0, INPUT_ANALOG);
+        pinMode(9, PWM);
+    }
+
+    void loop() {
+        int val = analogRead(0);
+        val = map(val, 0, 4095, 0, 65535);
+        analogWrite(9, val);
+    }
+
+
+See Also
+--------
+
+-  :ref:`constrain() <lang-constrain>`
+
+.. include:: /arduino-cc-attribution.txt