Do not share `treePaths` or `treeForMethods` on the prototype.

When shared on the prototype, any addon that modifies these paths will
change the `treePaths.vendor` location for ALL OTHER addons.
Merge pull request #2035 from rwjblue/dangit-javascript

Do not share `treePaths` or `treeForMethods` on the prototype.
Update CHANGELOG.

Updates to 7426bac2c.
Bump version.
Do not require addon tree to be present.
Merge pull request #2044 from rwjblue/allow-addons-without-addon-dir

Do not require addon tree to be present.
Use the correct addon name in addon generated package.json.
Merge pull request #2042 from rwjblue/use-the-proper-addon-name

Use the correct addon name in addon generated package.json.
Add `Registry.prototype.remove`.

Makes it possible to remove a preregistered plugin.
Add note to RELEASE doc: Update gh-pages/_config.yml version
Merge pull request #2049 from alexdiliberto/master

Add note to RELEASE doc: Update gh-pages/_config.yml version
Add `Registry.prototype.extensionsForType`.
Merge pull request #2048 from rwjblue/add-registry-remove

Add `Registry.prototype.remove`.
Merge pull request #2050 from rwjblue/extensions-for-type

Add `Registry.prototype.extensionsForType`.