doc: Update Readme

Fix typos, add USB support

Author: franky47

README.md

@@ -5,47 +5,48 @@
 [![GitHub release](https://img.shields.io/github/release/FortySevenEffects/arduino_midi_library.svg?maxAge=3600)](https://github.com/FortySevenEffects/arduino_midi_library/releases/latest)
 [![License](https://img.shields.io/github/license/FortySevenEffects/arduino_midi_library.svg?maxAge=3600)](LICENSE)
 
-This library enables MIDI I/O communications on the Arduino serial ports.
+This library adds MIDI I/O communications to an Arduino board.
 
 ### Features
 
+-   **New** : USB MIDI Device support with [`MIDIUSB`](https://github.com/arduino-libraries/MIDIUSB).
 -   Compatible with all Arduino boards (and clones with an AVR processor).
 -   Simple and fast way to send and receive every kind of MIDI message (including all System messages, SysEx, Clock, etc..).
 -   OMNI input reading (read all channels).
 -   Software Thru, with message filtering.
 -   [Callbacks](https://github.com/FortySevenEffects/arduino_midi_library/wiki/Using-Callbacks) to handle input messages more easily.
 -   Last received message is saved until a new one arrives.
 -   Configurable: [overridable template-based settings](https://github.com/FortySevenEffects/arduino_midi_library/wiki/Using-custom-Settings).
--   Create more than one MIDI port for mergers/splitters applications.
+-   Create more than one MIDI interface for mergers/splitters applications.
 -   Use any serial port, hardware or software.
 
 ### Getting Started
 
-1. Use Arduino's Library Manager to install the library.
+1. Use the Arduino Library Manager to install the library.
    ![Type "MIDI" in the Arduino IDE Library Manager](res/library-manager.jpg)
 
 2. Start coding:
 
-    ```c++
-     #include <MIDI.h>
+```c++
+#include <MIDI.h>
 
-     // Created and binds the MIDI interface to the default hardware Serial port
-     MIDI_CREATE_DEFAULT_INSTANCE();
+// Create and bind the MIDI interface to the default hardware Serial port
+MIDI_CREATE_DEFAULT_INSTANCE();
 
-     void setup()
-     {
-         MIDI.begin(MIDI_CHANNEL_OMNI);  // Listen to all incoming messages
-     }
+void setup()
+{
+    MIDI.begin(MIDI_CHANNEL_OMNI);  // Listen to all incoming messages
+}
 
-     void loop()
-     {
-         // Send note 42 with velocity 127 on channel 1
-         MIDI.sendNoteOn(42, 127, 1);
+void loop()
+{
+    // Send note 42 with velocity 127 on channel 1
+    MIDI.sendNoteOn(42, 127, 1);
 
-         // Read incoming messages
-         MIDI.read();
-     }
-    ```
+    // Read incoming messages
+    MIDI.read();
+}
+```
 
 3. Read the [documentation](#documentation) or watch the awesome video tutorials from [Notes & Volts](https://www.youtube.com/playlist?list=PL4_gPbvyebyH2xfPXePHtx8gK5zPBrVkg).