import REPL.jl code

Fixes #1773 (Repl autocompletion for composite type fields).
Fixes #3652 (Segfault during TAB-completion on OSX).
Fixes #4477 (Tab completion for `using` should look up installed packages).
integrate REPL.jl code into Base
expunge readline
fix repl crash when tab-completing type field
fix repl crash when pasting trailing newlines
add old-repl path completion behavior to new-repl

Cf. #5343
fix buffer size bug in Readline.edit_replace

A symptom of this is if

    ext(c)<left><left><left><tab><enter>

is entered into a fresh session, the output is

    extrema (generic function with 2 methods)

instead of the expected

    ERROR: c not defined
repl: fix color detection on windows
repl: bind Delete key
repl: don't ignore --no-history option

Also, hoist all the using/imports to the top.
cleanup base/Terminals.jl

- fix cmove_* fallbacks
- remove unused Colors & Attributes code
- get rid of submodules
- deindent
allow newlines after 'import X:'

For example,

    import Base:
        read,
        write
Fix #6281
Merge pull request #6296 from amitmurthy/amitm/shmemfix

Fix #6281
base/linalg/lapack.jl: Import PosDefException
Merge pull request #6298 from mschauer/posdefex

base/linalg/lapack.jl: import PosDefException
remove help categories (closes #6294)
add Google Compute Engine
Update README.md

Add section for building on Google Compute Engine, at least until OpenBLAS 0.2.9 is released and adopted with the patch for Sandybridge.
move list and tree examples to DataStructures

remove colorimetry, ndrange, and queue

use immutable in time example