Release version 0.9.3 (woocommerce#82)

Merge pull request woocommerce#76 from woocommerce/version/0.9.2

Release 0.9.2

Release version 0.9.1 (woocommerce#72)

Updating verion (woocommerce#68)

Bump version to 0.8.9

resetting 0.8.8

Bump version to 0.8.7

Only run if woocommerce is valid

This code checks if woocommerce is active and at least the minimum
version before initializing.

This also removes the previous notice.

Composer updates

* Adds fix to check for previously installed wc-api-dev by filesystem
check

* Checks for presence of installed woocommerce plugin before proceeding

Prepare composer compatibility (woocommerce#41)

* Add composer.json

This adds a composer.json so this plugin can be installed via composer.

* Adapt for composer use

1. Remove auto-update as it's no longer needed.
2. Add check to see if classes have already been defined
(this only happens in the transitionary period where the previously
installed instance of the plugin exists before it's deleted by wpcomsh)

* Don't load if the plugin has already been loaded.

There's a transitionary state that is possible.
This guards against it.

Also, it removes the rest of the auto updating code.

* Load plugin class dynamically

Because the plugin class can still be loaded by the existing installed
plugin, and there's no way to tell which way it was loaded, the main
plugin class is now moved to a separate file that is dynamically loaded
only after making sure it hasn't already been loaded by the previously
installed plugin.

* Update readme/versions

This updates the versions everywhere from 0.8.3 to 0.8.4
It leaves the stable version at 0.8.3 for now.
And updates the readme

* Corrections for notes

1. Fixed version format.
2. Fixed type on error notification