clean up usage
Fixing ssh_config proxy_command is not included
Remove website/ dir from gem [GH-2951]
Merge pull request #2950 from elyast/master

command/ssh-config: Fixing ssh_config, proxy_command is not included
Update CHANGELOG
Merge pull request #2948 from gnawhleinad/master

command/*: clean up usage
kernel/v2: capture error if provider config is bad [GH-2959]
core: Machine can set box
core: keep the same UI when handling a box URL
core: HandleBox keeps the same machine instance
website/www: feature preview blog post: rsync
website/www: ignore the standalone archive page
website/www: force up the version
website/www: fix downloads
core: Modify Bundler settings to work with restricted permissions

This includes two changes:

1. Change the Vagrant requirement to use the "= VERSION" constraint.
   The "path:" previously requires write permission in the directory
   of the gemspec, which we don't have in installers.

2. Set a BUNDLE_APP_CONFIG and BUNDLE_PATH setting. By setting this,
   Bundler won't ask for sudo password. Bundler never actually needs it;
   it is just overly aggressive in thinking it does.
core: chomp the version so we can echo into it
core: poll for process exit on SSH#exec with subprocess
core: make sure any Subprocess exits no matter what
guests/linux: public key insertion is more robust

contents can have newlines (or not)
Up childprocess dep to 0.4.1