fix to include beams built from src files in subdirs in modules list

Signed-off-by: Fred Hebert <mononcqc@ferd.ca>

Fix typespecs of new compiler behaviour

Updating manpages before 3.7.0

check last modified time on erl files for xrl and yrl files before compiling

Fix plugins list display to include project plugins

Support alias format {Namespace, Cmd} and {Namespace, Cmd, Args} (#1940)

add git clone --reference path support

fix install output result

templates/gitignore ignore emacs temp files

emacs creates temp files that ends with tilde (~).
These temp files should never be commited.
It is therefore safe to ignore them.

Signed-off-by: Niklas Johansson <raphexion@gmail.com>

Fix misleading config in app template

Uncommenting the sys.config shell setting in app template rebar.config
works now as expected.

Allow Breakpoints during task runs

This is mostly useful for tests, where a test suite of any kind can be
interrupted halfway through so that the user can probe the running
system to see what is happening.

This is done as follows:

1. the user must call `r3:break()` in a test suite
2. the user runs the task as `r3:async_do(ct)`
3. the test holds up and the user can do whatever
4. the user calls `r3:resume()` and the test proceeds as normal

A safeguard is added so that breakpoints are only triggered in the shell
in async mode

Sample session:

    $ rebar3 shell
    ...
    1> rebar_agent:async_do(ct).
    ok
    ...
    Running Common Test suites...
    %%% rebar_alias_SUITE: .
    === BREAK ===

    2> % <do some checks>
    2> r3:resume().
    ok
    3> .....
    %%% rebar_as_SUITE: ...........
    %%% rebar_compile_SUITE: ......
    ...

check if git/hg is installed

This PR is a simpler and mergeable version of #1853 by @shamis, since
the provider changed format enough to make merging difficult.

Compared to #1853, this also puts the responsibility on each resource to
check rather than adding a new optional callback.

The process dictionary is use as a warning/check cache.

Fallback when logging isn't initialized

In some cases, such as when the global rebar.config file contains typoes
and invalid terms, the rebar3 executable fails when trying to log the
error since it hasn't been set yet, such as in #1792

This patch fixes that by going for a fallback mechanism.

Fix shell hook expansion on windows

Dollar Variable expansion (`$VAR`) was inadvertently disabled for
windows variables, although %VARIABLES% already worked. This reduced the
portability of hooks in general.

Additionally, tests would fail on windows due to bad quoting of paths:
the path C:/a/b/c would fail when passed to the command
`cmd /q /c C:/a/b/c` because it would interpret /a /b and /c as 3
options. Using quotes makes the tests pass.

Refactor env path handling and fix some bugs related to it

app_info was turning any vsn into a binary which the vcs_vsn
function interprets as being an actual version and not something
like <<"git">>. original_vsn shouldn't be converted as it is then
not longer "original".

- Only set paths that need to be put as a priority
- Clean up paths before leaving API mode

The first point accounted for some performance cost, but the latter one
explains the 40% overhead in test runs: since rebar3 calls rebar3 a lot
with a bunch of fake apps, and that the new mechanism for path handling
by default does not _remove_ paths, it just _orders_ them, we would end
up in a situation where as the tests ran, more and more fake paths would
get added to the VM.

By the time the run was over, all path handling would take longer since
more paths needed filtering every time. By resetting paths at the end of
an API run, we prevent a given 'project' from polluting another one's
runtime and performance once the API successfully returns.

Some finishing touch to that code

Also handle some formatting

Move path management out of rebar_utils manual code path function
handling (which we leave there for backwards compat), and centralize
them to allow easier coordination of paths between plugins and deps.

On top of path handling, do a check of loaded modules to only purge and
reload those that actually need it done in order to prevent all kinds of
weird interaction and accidental purge kills. It also allows the
possible cohabitation of both at once, with a "in case of conflict pick
X" as a policy

Changing path handling in providers also highlighted a bunch of bugs in
some tests and appears to fix some in other providers, specifically
around plugins.

Re-add erlc compiler; plugins need it

However, we add a once-printed deprecation warning for the new
interface.