Package should have download options
Package options must be passed as argument to downloader
Package options should be dumped if exists
Package options must be a non mandatory array and should be loaded when
exists
Repository options must be replicated on package when dist file is under
repository base dir
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/Composer/Downloader/FileDownloader.php
Merge remote-tracking branch 'lcobucci/master'

Conflicts:
	src/Composer/Downloader/FileDownloader.php
Only load options when they come from the lock file, not from standard metadata, refs #2189
Rename options to transport-options, refs #2189
Handle alias packages properly, refs #2189
Also load transport options in filesystem repositories to avoid loss from the installed repo, refs #2189