Docs clean up part 1

Big push on getting the docs cleaned up before 1.0. Proper wrapping of
everything so it's decently viewable from the command line (or as
decently viewable as markdown can be - the tables will never look great
from the command line).

Only one code change in this PR: rename bouncetime to bounce_time
(everything else is PEP-8, so this probably should be too) and change
its units to seconds from milliseconds (again, all other durations in
the library are in seconds, so it feels inconsistent that this one
isn't; for the sake of those who won't read the docs - which is most
people - I figure consistency helps with guessing!).

docs/notes.md

@@ -2,7 +2,8 @@
 
 1. **BCM pin numbering**
 
-    This library uses BCM pin numbering for the GPIO pins, as opposed to BOARD. Unlike the `RPi.GPIO` library, it is not configurable.
+    This library uses Broadcom (BCM) pin numbering for the GPIO pins, as
+    opposed to BOARD. Unlike the `RPi.GPIO` library, this is not configurable.
 
     Any pin marked `GPIO` can be used for generic components.
 
@@ -36,11 +37,11 @@
     - *5V = 5 Volts*
     - *DNC = Do not connect (special use pins)*
 
-1. **Wiring**
+2. **Wiring**
 
     All components must be wired up correctly before using with this library.
 
-1. **Keep your program alive with `signal.pause`**
+3. **Keep your program alive with `signal.pause`**
 
     The following program looks like it should turn an LED on:
 
@@ -52,9 +53,12 @@
     led.on()
     ```
 
-    And it does, if you're using the Python shell, IPython shell or IDLE shell, but if you saved this program as a Python file and ran it, it would flash on for a moment then the program would end and it would turn off.
+    And it does, if you're using the Python shell, IPython shell or IDLE shell,
+    but if you saved this program as a Python file and ran it, it would flash
+    on for a moment then the program would end and it would turn off.
 
-    The following file includes an intentional `pause` to keep the program alive:
+    The following file includes an intentional `pause` to keep the program
+    alive:
 
     ```python
     from gpiozero import LED
@@ -67,9 +71,11 @@
     pause()
     ```
 
-    Now running the program will stay running, leaving the LED on, until it is forced to quit.
+    Now running the program will stay running, leaving the LED on, until it is
+    forced to quit.
 
-    Similarly, when setting up callbacks on button presses or other input devices, the program needs to be running for the events to be detected:
+    Similarly, when setting up callbacks on button presses or other input
+    devices, the program needs to be running for the events to be detected:
 
     ```python
     from gpiozero import Button