PlatformIO Library Manager manifest file

* This library in Web: http://platformio.ikravets.com/#!/lib/show/SFE-Arduino-CC3000
* Specification: [PlatformIO Library Manager](http://docs.platformio.ikravets.com/en/latest/librarymanager/index.html)
* Integration: [IDE Integration](http://docs.platformio.ikravets.com/en/latest/ide.html)

`library.json` is a library manifest file which can be used with different tools/managers to organise embedded libraries. Currently, only [PlatformIO](http://platformio.ikravets.com) uses it.  How does this look from CLI:

```bash
$ platformio lib search “+arduino +cc300“
# Found ... libraries:
# SFE-Arduino-CC3000        Arduino library for the TI CC3000 WiFi Shield and SparkFun Breakout Board

$ platformio lib install SFE-Arduino-CC3000
# Installing SFE-Arduino-CC3000  library:
# Downloading  [####################################]  100%
# Unpacking  [####################################]  100%
# The library ‘SFE-Arduino-CC3000' has been successfully installed!

$ platformio lib show SFE-Arduino-CC3000
# SFE-Arduino-CC3000
# -------------
# Author: SparkFun Electronics
# Keywords: wifi, wi-fi, http, web, server, json, rest, spi
# Version: ***
#
# Arduino library for the TI CC3000 WiFi Shield and SparkFun Breakout Board

$ platformio lib update
# Updating SFE-Arduino-CC3000  library:
# Versions: Current=***, Latest=***       [Up-to-date]
```
Merge pull request #6 from ivankravets/patch-1

PlatformIO Library Manager manifest file