Fix two annoying warnings

[fredrikekre]

Fixes:

julia> using <TAB>WARNING: both Pkg and Base export "rm"; uses of it in module Main must be qualified
julia> using

and

julia> error()
ERROR: 
Stacktrace:
 [1] error() at ./error.jl:42
 [2] top-level scope

julia> 1<Ctrl+Q>WARNING: Base.edit is deprecated: it has been moved to the standard library package `InteractiveUtils`.
Add `using InteractiveUtils` to your imports.
 in module Base
WARNING: Base.edit is deprecated: it has been moved to the standard library package `InteractiveUtils`.
Add `using InteractiveUtils` to your imports.
 in module REPL
in #59 at /home/fredrik/julia-master/usr/share/julia/site/v0.7/REPL/src/REPL.jl