Displays package caching actions

use ~ts for unicode output and reset encoding to latin1

Utf8 tree

This makes it obvious where packages are cached and when the cache is
being reused.

Messages are of the form:

===> Fetching recon ({pkg,<<"recon">>,<<"2.2.0">>})
===> Downloaded package, caching as
$HOME/.cache/rebar3/hex/default/packages/recon-2.2.0.tar

and

===> Fetching recon ({pkg,<<"recon">>,<<"2.2.0">>})
===> Version cached at
$HOME/.cache/rebar3/hex/default/packages/recon-2.2.0.tar is up
to date, reusing it

set parent on already fetched apps so tree works

Use raw bytestream when writing files

This patch forces write_file_if_contents_differ/2 to use raw bytes as
when writing files. This fixes an issue where UTF-8 characters are
processed and written back as ISO-8859-1 into the file, which makes it
impossible to use UTF-8 characters in .app.src files.

remove replacement of home dir with ~ in update output

symlink ct test dirs rather than copy

add support for `rebar3 eunit --file=...'

support pkg attribute on dep to declare package name different from app name

upgrade relx and bbmustache

fix pkgs provider output for new package index format

don't error on upgrade if user removes top level dep

add error message for dependency that doesn't contain single app dir

override 'deps' now automatically overrides '{deps,default}'

improve error messages for packages by checking its existance before fetch

don't store deps list with duplicate in state

use 'default' for default hex repo path in cache and include in info messages

update erlcinfo on disk if source file removed

do not override user cli supplied outputdir for relx

this patch treats pkg and src deps as equals, so level decides winner

Instead fetching and resolving src deps (which could depend on pkg deps)
and then pkg deps this patch combines the two into a single set of
iterations by level. The only difference between src and pkg deps in this
new install_deps is how their deps list is found -- from the config or
lock file for src deps and from the neighbors of the vertex for pkg.

fix leaking hex_registry table