Problem: An "after" directory of a package is appended to 'rtp', which
will be after the user's "after" directory. ()
Solution: Insert the package "after" directory before any other "after"
directory in 'rtp'. (closes#3409)
Problem: Package directory not added to 'rtp' if prefix matches.
Solution: Check the match is a full match. (Ozaki Kiichi, closes#2817)
Also handle different ways of spelling a path.
Problem: When package path is a symlink adding it to 'runtimepath' happens
at the end.
Solution: Do not resolve symlinks before locating the position in
'runtimepath'. (Ozaki Kiichi, closes#2604)
Problem: :packadd does not load packages from the "start" directory.
(Alejandro Hernandez)
Solution: Make :packadd look in the "start" directory if those packages were
not loaded on startup.
Problem: The packadd test does not create the symlink correctly and does
not test the right thing.
Solution: Create the directory and symlink correctly.
Problem: When using a symbolic link, the package path will not be inserted
at the right position in 'runtimepath'. (Dugan Chen, Norio Takagi)
Solution: Resolve symbolic links when finding the right position in
'runtimepath'. (Hirohito Higashi)
Problem: For plugins in packages, plugin authors need to take care of all
dependencies.
Solution: When loading "start" packages and for :packloadall, first add all
directories to 'runtimepath' before sourcing plugins.
