Support path replacement of ~ with $HOME

[diegozea]

julia> cd("~/.julia/Profile/src/")
chdir: No existe el archivo o el directorio
 in system_error at error.jl:22
 in cd at file.jl:14

julia> cd("/home/dzea/.julia/Profile/src/")

julia> cd("~")
chdir: No existe el archivo o el directorio
 in system_error at error.jl:22
 in cd at file.jl:14

julia> cd("/home/dzea")

julia> cd("./.julia/Profile/src/")

[pao]

I've changed the issue title to clarify; let me know if I misunderstand you.

[diegozea]

Thanks :) it's exactly what I want to say

[JeffBezanson]

expanduser does this. Also dup of #1136.

[pao]

We'll close as dup then.