Refactor install deps

Old one might have been a mistake; this one works fine.

- Make functions shorter
- Unnest some functions
- Split up and give names to major conditional branches

follow xdg standard. fixes #122

cmake template

check for newly added deps in the config file that aren't level 0 in lock

update project app list with new appinfo records after build

use project sub-apps with deps in their rebar.config

fix error where an exception in ct could hang rebar by monitoring

the process where ct is performed

suppress common_test output unless `rebar3 ct` is run with verbose switch

purge mods loaded during check to see if they need to be recompiled

during compile task before running subsequent tasks

check already compiled modules compile arguments against current compile arguments

Replace package management with hex.pm

arguments to ensure compile results as as intended

Initial `deps` command

needs_update: on ref defined deps only have to match prefix if 7+ chars

Dialyzer: Remove extra default warnings

It is not convenient for everyone to handle unmatched_returns and
underspecs warnings. Extra default warnings are removed to match
dialyzer's behaviour.

Fix {dialyzer_plt_warnings, false}

Previously dialyzer would crash when not doing success typing analysis.

When dialyzer_plt_warnings is false no warnings should be returned when
updating a PLT. Previously any callgraph warnings would be returned when
updating a PLT regardless of the get_warnings option.

Initial WTF provider implementation

Fix #140 and preserve erl_first_files order

Match erl_first_files properly against all files needing
compilation and make sure the order of erl_first_files as specified in
rebar.config is preserved (rebar/rebar#445)

Tests missing

Upgrade procedure, from scratch (WIP)

Apps that are no longer used are not automatically deleted, but we tell
users it can be done. This is safer while we're not sure of the
correctness of these messages.

Error messages are added for transient dependencies and dependencies not
found.