CI: Run 'dub build' and 'dub test' on Windows

Merge pull request #1953 from Geod24/attributes ...

Make CommandLine's constructors '@safe pure nothrow'
merged-on-behalf-of: Nicholas Wilson <thewilsonator@users.noreply.github.com>

Make CommandLine's constructors '@safe pure nothrow'

Resolve deprecation warnings.

Fix failing test on native Windows.

Add a workflow to run the test-suite on Ubuntu 18.04 and Mac OSX ...

Using Github actions gives much more control to contributors.
Ultimately, we'd like to add Windows support too,
but currently the testsuite is too tied to POSIX.

Testsuite: Make timeout test properly fail on command not found ...

For example, if netcat is not installer, this test will happily pass.

Testsuite: Add no-test to copyFiles test ...

This test is only supposed to be run, not unittested.
It can create a problem when one wants to re-run the test suite,
as if the unittest have been built, there's an extra file in the bin directory,
which in turns makes the test fail.

testsuite: Use '|| true' when pipefail is involved ...

On Mac OSX, this script fails because of the behavior of pipefail.
A simple ' || true' solves the problem, while 'grep' still ensures
it behaves as expected.

testsuite: Replace a non-portable usage of rm (!) with dub clean ...

Who would have known that the following would pass on Linux but not Mac OSX:
---
touch file
rm -f file/nonono
---
Well surely not me. And indeed "b" is a file, not a directory,
so this rm didn't make sense. Just use dub clean. Like the rest of us.

testsuite: Skip gtkd test on non-Linux platform ...

This currently fails on Mac because the '.so' is hardcoded.
It should eventually be fixed, but for the time being,
my objective is to get things to pass on my machine.

testsuite: Make issue1117 test re-runnable ...

It's the little things in life, like being able to re-run your test-suite
on your own machine, that makes the greatest joy.

testsuite: Make test for issue1091 re-runnable ...

After the initial run, one couldn't run this test again as the expected message
'building configuration' would not be printed anymore.

testsuite: Document what interactive remove is doing and make it reproducible ...

It's a terrible solution, but it works for the time being.

Merge pull request #1868 from myfreeweb/patch-1 ...

ldc: support --arch=aarch64 and powerpc64
merged-on-behalf-of: Mathias LANG <pro.mathias.lang@gmail.com>

ldc: support --arch=aarch64 and powerpc64 ...

Because Meson calls e.g. `dub describe something --arch aarch64`

Merge pull request #1945 from Geod24/improve-cross-platform ...

Make some tests runnable on Mac OSX

Merge pull request #1938 from shoo/fix_issue1040 ...

fix #1040 - dub run <package>@x.y.z ignores the specified version
merged-on-behalf-of: Mathias LANG <pro.mathias.lang@gmail.com>

Fix #1040 - dub run <package>@x.y.z ignores the specified version

testsuite: Use POSIX's -b -B options instead of GNU-specific -Z

testsuite: Replace GNU-specific -f option with a custom implementation ...

This will allow Mac OSX users to run that part of the testsuite

Use a value < ushort.max for tests using the test_registry ...

It is possible for the PID to be >= 65536, in which case the dub_registry
would fail to parse the argument and error out.
This can be frequently experienced on long running systems,
for example Mac OSX.

test_registry: Parse the port as a ushort, not a uint ...

Otherwise we get a failure inside Vibe.d when the port is > ushort.max,
which can happen easily, e.g. on Mac OSX.

Add generated man pages to gitignore

Merge pull request #1944 from Geod24/badges ...

Update Travis badge to .com instead of .org

Merge pull request #1942 from MartinNowak/merge_stable ...

merge stable

Update Travis badge to .com instead of .org ...

The repository was migrated.

Merge remote-tracking branch 'upstream/stable' into merge_stable

purge changelog

update version to v1.21.0