v1.1.1.rc1: Merge pull request #244 from dberzano/no-incremental-if-first-failed

• Do not run the incremental recipe if the first build has failed (#174)
• alienv complains if attempting to load a non-existing package (#237)
• alienv prints the just-loaded packages in enter and load (#237)
• Better architecture detection (#222)
• Ship alienv shell helper with the pip distribution (#227)