Update changelog
make ruby-version file to work with rbenv
Fix examples for `update_all` to use `$set`
Bump to bson rc2
Allow string write concern keys
Allow string read preference values
Call moped 2.0.0.beta
small refactoring on instrumetation
both threads should wait on pool_spec
revert change on ruby-version
remove instrument log on address error
add timeout to address resolve
fix pool_spec
fixing pool_spec.rb
Query cursor should always return a Enumarable and not Enumerator.

The Enumerator.next implementation is different on MRI and JRuby.
JRuby spins a new thread to fetch the .next element,
which will cause Moped to get a new connection in the pool.
Having those different implementations, lead us to not return Enumerator to avoid user mistakes.

For an example of the different implementation see: https://gist.github.com/arthurnn/6734205
Update changelog
Typo [ci-skip]
Merge pull request #217 from mongoid/timeout_on_resolve

add timeout to address resolve
Merge pull request #213 from Lytol/update_all_documentation

Fix examples for `update_all` to use `$set`
No longer attempt to refresh arbiters.

[ fix #210 ]