Add AK4558 CODEC support / Merge branch 'master' of https://github.com/MickMad/Audio

This reverts commit f0b376d3f6.

Adding useful functions to setup all the configurable options in the
CODEC (not yet finished)

https://forum.pjrc.com/threads/32252-Different-Range-FFT-Algorithm?p=91895&viewfull=1#post91895

More waveforms

One write was out-of-bounds due to worng address put (I was using the
device address rather than the register address), another write
overwrote the Power Management register with the Mode Control register.
Now everything works. Added two exampes: SineOutTest that puts two
sinewaves on the outputs, and PassthroughTest that connects the two
inputs to the two outputs.

This reverts commit 8d8350bf07.

The address was wrongly put to 0x10 + the two hardware set bits, while
it has to be 10 decimal, or 0x0A. Silly me.

The PIN_PDN was not set as output, therefore it would not transition to
LOW for 150 ns and then stay HIGH to properly enable the CODEC. The
CODEC now powers up, at least.

The test puts a 440 Hz sinewave on one channel, and a 220 Hz on the
other

Merging updates from PaulStoffregen/Audio to my fork

Some issues fixed (#92, #56)

Fixed: issue #56 - import and cut, copy & paste works fine, I added a routine which increments the numbers at the end of the names, IDs will be generated automaticcaly, if the ID already exists, and the appropriate name will be increased (e.g. "mixerRight" -> "mixerRight0", "input3" -> "input4" etc.)

Add CI build status

Skip unused source files

continuous integration: Add arm_cortexM4l_math library to linker

Continuous Integration

Hi @PaulStoffregen,

I see that your project contains the practical examples. All of us understand that it’s not easy to test them before each new commit to this repository. What is more, need to be sure that all of these examples are actual and compile without errors.

I propose to solve this task using [Continuous integration](https://en.wikipedia.org/wiki/Continuous_integration) practice which is intended to detect [integration bugs](https://en.wikipedia.org/wiki/Software_testing#Integration_testing) and save time over the lifespan of a project.

## How does it work?
The each new commit to this repository will be tested using existing examples with appropriate platforms/embedded boards. @PlatformIO is used here as cross-platform code builder and library manager in pair with @travis-ci (distributed continuous integration service). 

## Quickstart
Please enable @travis-ci following the steps 1, 2 and 5 here http://docs.travis-ci.com/user/getting-started/#To-get-started-with-Travis-CI%3A 

For more details please follow to:

* Official Travis CI Documentation for PlatformIO: https://docs.travis-ci.com/user/integration/platformio/
* PlatformIO documentation for Travis CI: http://docs.platformio.org/en/latest/ci/travis.html

## Status Badge
You can add [badge with build status](https://docs.travis-ci.com/user/status-images/) to your README

**Markdown**
```
[![Build Status](https://travis-ci.org/PaulStoffregen/Audio.svg?branch=master)](https://travis-ci.org/PaulStoffregen/Audio)
```

**RST**
```
.. image:: https://travis-ci.org/PaulStoffregen/Audio.svg?branch=master
    :target: https://travis-ci.org/PaulStoffregen/Audio
```

## Examples

* Project [USB_Host_Shield_2.0](https://github.com/felis/USB_Host_Shield_2.0) [![Build Status](https://travis-ci.org/felis/USB_Host_Shield_2.0.svg?branch=master)](https://travis-ci.org/felis/USB_Host_Shield_2.0)
* Project [Arduino-IRremote](https://github.com/z3t0/Arduino-IRremote) [![Build Status](https://travis-ci.org/z3t0/Arduino-IRremote.svg?branch=master)](https://travis-ci.org/z3t0/Arduino-IRremote)
* Project [ethercard](https://github.com/jcw/ethercard) [![Build Status](https://travis-ci.org/jcw/ethercard.svg?branch=master)](https://travis-ci.org/jcw/ethercard)

Handle all nested examples

More examples for http://platformio.org/#!/lib/show/70/Audio

Again import improvements

Add dependent SerialFlash library