Add mcp23008 support (#649)

* Add support for mcp23008 8-port io expander

* add-mcp23008-support

* Revert "add-mcp23008-support"

This reverts commit b4bc7785b19bf27843b140e56707b935716e3759.

* Fixed spacing typo

* removed extra space in mcp23008.cpp, line 23

* Fixed trailing whitespace issue

* Added mcp23008 component

* Added component mcp23008

* Edited typo in test/test1.ymal

Removed additional ' in line 1337

* Another typo

tests/test1.yaml

@@ -725,12 +725,20 @@ binary_sensor:
       mode: INPUT
       inverted: True
   - platform: gpio
-    name: "MCP binary sensor"
+    name: "MCP21 binary sensor"
     pin:
       mcp23017: mcp23017_hub
       number: 1
       mode: INPUT
       inverted: True
+  - platform: gpio
+    name: "MCP22 binary sensor"
+    pin:
+      mcp23008: mcp23008_hub
+      number: 7
+      mode: INPUT_PULLUP
+      inverted: False
+
   - platform: remote_receiver
     name: "Raw Remote Receiver Test"
     raw:
@@ -847,6 +855,13 @@ output:
       number: 0
       mode: OUTPUT
       inverted: False
+  - platform: gpio
+    id: id23
+    pin:
+      mcp23008: mcp23008_hub
+      number: 0
+      mode: OUTPUT
+      inverted: False
   - platform: my9231
     id: my_0
     channel: 0
@@ -1372,6 +1387,10 @@ pcf8574:
 mcp23017:
   - id: 'mcp23017_hub'
 
+mcp23008:
+  - id: 'mcp23008_hub'
+    address: 0x22
+
 stepper:
 - platform: a4988
   id: my_stepper