First pass at official user-env-compile plugin

- Uses ENV and APP/ENV files
- Supports old BUILD_ENV files (which are likely in wide-use)
- Allows user's to override globals with app-specific configuration

Closes #284
Closes #683
Closes #763

Refs #503
Refs #678
Point users to upgrade guides
Merge pull request #801 from joelvh/patch-1

Point users to upgrade guides
Fix crt/key check
Merge pull request #805 from ademuk/patch-1

Fixed import-ssl server.crt/key check
Dokku pushes now happen as the dokku user, not git. Refs #796
Merge pull request #806 from progrium/fix-remote-user

Dokku pushes now happen as the dokku user, not git. Refs #796
Force install a default nginx.conf. Closes #799
Ensure ruby is installed when running the dokku-installer
Merge pull request #807 from progrium/799-force-nginx-conf

#799: Force nginx conf
Ensure makefiles are properly formatted
Merge pull request #808 from progrium/proper-editorconfig

Ensure makefiles are properly formatted
Release 0.3.8
Fix reference to $APP
Remove extra reload command
Combine calls to restart nginx into a single command
one-liner
Remove extra dash
Use a template to create an application's nginx.conf
Allow overriding of the nginx.conf template via nginx.conf.template