Update Alert to 0.9.0, .gitignore, composer.lock

 - Update Alert to v0.9.0 in composer and submodule
 - Update .gitignore to ignore composer data in
   vendor directory
 - Add composer.lock to repo
Merge branch '0.2'

Conflicts:
	composer.lock
Update predis dep version to ~0.8.6
Convert Resolver to unified interface
Implement OrderedResolverStrategy properly
Improve IP literal resolution resiliency

Allow [xxx] syntax for IPv6 addresses, to facilitate usage with directly parsed URI components