Replace custom lifecycle with AS::Notifications
Merge '2-8-stable' into devin/as_instrumentation
Revert unintended change

Not sure why this got deleted. It was not intentional
Provide a friendly transition path

This will warn users that Lifecycle events are being deprecated in favor
of active support notifications.
Make deprecation warnings more visible
Fix whitespace error
Use $stderr to print deprecation warnings
Modify $LOAD_PATH in lib/protobuf/descriptors so that other plugins may use the descriptors in their own protoc-gen-foo compilers
Add console task for development funsies
Add protobuf:compile rake task for external use

The `protobuf:compile` task can be utilized in any project or gem that
uses protobuf. Open up the Rakefile of the including project and add:

```ruby
require ‘protobuf/tasks’
```

The `compile` task accepts three arguments: package, source, and
destination. Package does not have a default value and must be
specified. Source’s default is ‘defintitions’. Destination’s default is
`lib`. Plugin’s default is `ruby`, and is overridable in case you want
to utilize the descriptors to make your own plugin generator.

The composed command to protoc is printed to the terminal and then the
process is exec’d with that command.
Add protobuf:clean task for external use

To get this task simply `require ‘protobuf/tasks’` in your Rakefile.

Clean will ask for confirmation of removing previously compiled pb.rb
source files. You can skip the confirmation step by providing
PB_FORCE_CLEAN=1. A force clean is automatically invoked from the
`compile` task unless PB_NO_CLEAN=1 is specified.

The package argument must be specified. The destination argument
defaults to `lib`.
Merge pull request #139 from devin-c/devin/as_instrumentation

Replace custom lifecycle with AS::Notifications
Merge pull request #141 from localshred/bj/plugins-stable

Make it easier to include descriptors in external gems
Merge pull request #142 from localshred/bj/rake-tasks

Add protobuf:clean and protobuf:clean rake tasks for external use
Change README to reference the github wiki for installation and usage
Bump version 2.8.9
Fix link references in README
Update README url to the wiki
Allow passing a file extension to the compile and clean rake tasks

Allows external gems to use these tasks by specifying the types of
files they intend on generating, such as `.h` or `.myaweomseplugin.rb`.
The default is of course `.pb.rb` as that is the extension of files
generated from this library.
Merge pull request #143 from localshred/bj/compile-file-extension-arg

Allow passing a file extension to compile/clean