Mention `build_image` YML option
Replace `build_environment` by `build_image`
Merge pull request #96 from bittner/master

Mention `build_image` YML file option for selecting minion
updated link for sample projects
Merge pull request #97 from vidyar/update_url

updated link for sample projects
updated permissions
updated custom_images
removed the build_environment tag from languages
Merge pull request #98 from vidyar/custom_image_branch

Custom image branch
added space
Merge pull request #99 from vidyar/custom_images_branch-1

added space