Improve merge of command line options and config options in CT

refine eunit test detection

application modules will be added to the eunit test set automatically, no
need to consider them for inclusion in the test set separately

... before calling erlang:function_exported(ct_testspec,get_tests,1).

stops the eunit provider from filtering out test modules based on the
file extension. previously, it was hardcoded to expect all test files
ended in `.erl`. this change allows for endings like `.lfe` and `.beam`

Parse given test specs and add all spec- and suite directories as
extra_src_dirs in order to ensure that all these directories are
copied to the _build area and the suites are compiled.

Specs located in the project- or app root are explicitly copied to the
_build area in order to avoid recursive copying of the complete
directory tree.

shell: don't crash apps that use release version operators

the releases website has changed

Like for instance: {app, "0.1.0", '='}

Add rebar3.crashdump to gitignore template

Fix regex match for ignored file

add `get-deps` provider

The regex mistakenly matched too many files (any character followed by
an underscore) rather than only files starting in '._'

This properly escapes the expressions to work in all cases.

This is a bugfix. It makes sure that the given path to a testspec is
translated so common_test will pick the spec from the _build
directory, and not from the source tree.

Update THANKS

This is necessary in order to automatically get the testspec included
as an artifact (i.e. copied to the _build dir) in the case when it is
stored in another directory than 'test'.

Select git clone command by git version

The option --single-branch was introduced in git version 1.7.10 and
thus rebar3 cannot fetch git dependencies on systems where earlier
git versions are install.

This commit will select other git clone commands if an earlier git
version is detected. If the git version cannot be determined rebar3
falls back on the previous behavior and uses --single-branch.

a no-op provider that depends on lock that is slightly more discoverable and user friendly

Bug: option 'spec' is not specifically handled when merging options
from the command line with options from rebar.config. Due to this, if
the config specifies a 'spec', then this will take precedence over any
'dir' and/or 'suite' on the command line.

This commit takes special care of all options that can be used to
select tests - meaning that if any of the options 'spec', 'dir',
'suite', 'group' or 'case' are specified on the command line, then all
'spec', 'dir', 'suite', 'group' and 'case' options in rebar.config
will be ignored.

Restrict regexp to match on files starting with '._'

Correct precedence of compile options merged from profiles.

Ensures merged compiler options end up in the correct order to maintain profile precedence.

Moves the merge functionality from rebar_opts:merge_opts/2 to a standalone function to ease extension and debugging.

Replace unprocessed ~n linebreaks

Fixes #1392

Includes improvments and function documentation for all modules (in
alphabetical order) up to rebar_core, and may have included more in
other modules as I saw fit to dig and understand more of the internals.

Upgrade relx, erlware_commons and cf

relx ~> 3.22.0
erlware_commons ~> 0.22.0
cf ~> 0.2.2

Add 'recursive' option