Refactor require-dev handling to use one single repository and a one pass solving, fixes #719, fixes #1185, fixes #1330, fixes #789, fixes #640
Enable dev mode by default in update command, add a --no-dev flag, fixes #1005
Remove all occurrences of getLocalDevRepository and getLocalRepositories calls
Purge old dev packages before installing/updating new ones to make sure people do not have issues updating
Update docs, fix tests
Add @deprecated note
Merge pull request #1644 from Seldaek/newdevrequires

New require-dev handling