SSHKit::Command: Changed it include the exit status code in the exception message generated by #exit_status=.  This information is often useful, for example when the command was not found on the remote system.
Fix "undefined method `verbosity'" error in the Pretty formatter
Use a connection pool to reuse SSH connections.

Using a connection pool saves time of negotiating a new SSH
connection for every SSHKit `on()` block. When testing with a simple
capistrano recipe, a `cap deploy` ran 10-15% faster with this
connection pool.

By default, an existing pooled connection will be replaced with a
new connection if it hasn't been used for more than 30 seconds. This
can be changed, e.g.:

```
SSHKit::Backend::Netssh.pool.idle_timeout = 60 # seconds
```

Setting the timeout to 0 will disable pooling (connections will not
be reused).

Note that the connection pool will not recover gracefully if a
connection somehow "goes bad". For example, if the server closes an
idle connection, or if the underlying socket gets reset, a subsequent
command sent to that server could fail, and the command will not be
retried with a new connection. Therefore it is a good idea to use a
conservative (small) value for the idle_timeout.
Implement `:limit` for `groups`.

Leave it unimplemented for `parallel`, and fix the README example.
Fix #75, SSHKit::Formatter.Dot prints dots

Change line 10 in lib/sshkit/formatters/dot.rb from `obj === SSHKit::Command` to `obj.is_a? SSHKit::Command` to better object comparision.
Add tests for SSHKit::Formatter.Dot
Test SSHKit::Formatter.Dot for passing commands and failing commands
Test SSHKit::Formatter.Dot for SSHKit::LogMessage
Fix #74, SSHKit::Configuration.format picks up on BlackHole

Change lib/sshkit/configuration.rb#L46 to pick up on constants that have more than one capitals by matching downcased format name and constant name.
Test ability to change format to `:BlackHole` (or `:blackhole`) as well as `:dot`
Merge pull request #72 from phs/phs/limit

Implement `:limit` for `groups`.
Add license to gemspec
Merge pull request #77 from anatol/patch-1

Add license to gemspec.
Merge pull request #76 from hab278/master

Formatters can have more than one capitals in there name and SSHKit::Formatter.Dot prints out dots.
Merge pull request #70 from mbrictson/ssh-pool

Use a connection pool to reuse SSH connections.
Ignore everything Vagrant related
Preparing Release v1.3.0
Fixing link to travis-ci so the badge works properly
Merge pull request #79 from BukhariH/Fix_ReadMe

Fixing link to travis-ci so the badge works properly
Fix typo.
Merge pull request #80 from seanhandley/typo

Fix typo.
Refer to all_servers array defined earlier.
Add GFM for code examples.
Merge pull request #82 from seanhandley/GFM

Refactor code samples to use GFM.