Upgrade Vagrant to 1.4.1 for tests
Set config values to `false` for empty strings

Simplifies logic when checking the value.
Add default scheme and port to Apt config values already when finalizing

Allows their usage as URIs.
Drop default scheme and port mentions of Apt documentation

*The functionality will be deprecated in v2.0.0*
README.md - conditional plugin specific configs

Suggesting wrapping the plugin specific configuration into Vagrant.has_plugin block, preventing issues in case Vagrantfile is shared with someone not having proxyconf installed or plugin temporarily uninstalled (for development/testing etc).
Merge pull request #43 from tuminoid/patch-1

README.md - conditional plugin specific configs
Make Vagrant version configurable for testing

`VAGRANT_VERSION` environment variable can be used for specifying the
wanted Vagrant version. Defaults now to v1.4.2.
travis: Test against master all supported minor Vagrant versions

Use correct Ruby version with each Vagrant version.

Allow the master build to fail. (And it will now as
`Vagrant.require_plugin` is deprecated.)
Merge branch 'test-multiple-vagrant-versions'
Extract `Plugin.check_vagrant_version` helper
Adapt plugin loading for Vagrant 1.5

`Vagrant.require_plugin` will be deprecated in Vagrant 1.5.

In new Vagrant versions we now use `require` directly for loading the
optional dependencies. All exceptions are logged but ignored. Vagrant
itself will handle the real errors later (or has already errored out).
Merge pull request #44 from tmatilai/require_plugin_deprecated

`Vagrant.require_plugin` will be deprecated in Vagrant 1.5
Update the changelog
Up version to 1.1.0.dev
readme: Add a note about `Vagrant.has_plugin?` usage

Also remove the check from env_proxy example.

[ci skip]
env_proxy: Quote `no_proxy` to protect it from spaces

Unfortunately we can't escape other values before v2.0 as even the
README had an example of using shell variables in the last release.

Fixes #42
Store machine into instance variable on actions

Remove the need to pass `machine` and `config` instances through all
methods.
Move `escape` helper from `Action::ConfigureYumProxy` to `Action::Base`

Allow other actions to use it too.
Gitignore vagrant-proxyconf-*.gem files everywhere

[ci skip]
Add support for Git proxy through system config.

This adds support for overriding the HTTP proxy for Git by setting the
system configuration. It uses the git command itself to write to the
config file.