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

changelog and update version to v1.7.1-beta.1

Merge pull request #1333 from dkgroot-dlang/dragonflybsd-master ...

Add support for DragonFlyBSD

Fix buildsettings.d according to Sebastian Wilzbach notes ...

Style, NativePath memoizing, more refactoring

See https://github.com/dlang/dub/pull/1335 for details

download timeouts ...

- 8s by default
- only for curl atm.

Add support for DragonFlyBSD ...

- Switch from /bin/sh to /usr/bin/env bash
- Ignore temporary and test-build files (gitignore)
- Untrack changes to source/dub/version_.d
- Handling 'isDragonflybsd'
- Use 'tr -d' instead of 'tr --deleted' which works on Linux and BSD based platforms
- Fix FRONTEND = unbound variable (test/run-unittest.sh)

buildsettings.d refactored to more std library usage

Merge pull request #1330 from mathias-lang-sociomantic/dix-758 ...

Do not abort if the directory already contains a .gitignore
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

Merge pull request #1326 from wilzbach/upgrade-vibe-d ...

Bump vibe.d version used for 'dub init'
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

Do not abort if the directory already contains a .gitignore ...

It's a very annoying 'feature' to Github users.

Bump vibe.d version used for 'dub init'

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

update version to v1.7.0

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

update version to v1.7.0-rc.1

speed up platform probe 50ms -> 5ms by avoiding phobos imports

fix #1320, Add an option to hide warnings

Merge pull request #1311 from MartinNowak/merge_stable ...

Merge remote-tracking branch 'upstream/stable' into merge_stable
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

rewrite generator targets configuration ...

- as discusses in in https://github.com/dlang/dub/pull/1128 change the
  configuration algorithm to solve polluting sibling dependencies with
  compiler flags (e.g. versions), thus making it possible to better
  reuse cached builds

0. collect dependencies and shallow configuration
1. downwards inherit versions, debugVersions, and inheritable build options
2. define Have_dependency_xyz for all direct dependencies
3. upwards inherit dflags, versions, debugVersions, import paths,
    string import paths (and libs, lflags for static libs)
4. override string import files in dependencies

update changelog and version to v1.7.0-beta.1

Fix sublime text generator file regex ...

Errors were not displaying properly in sublime text before because of the extra empty group capture. 
That group was being interpreted at the error text when the one right after is actually the error text.

Fix #895, so that dub looks for a compiler next to itself first. Also, ...

put some restrictions on the defaultCompiler specified in a DUB
settings.json, such that it must be a compiler name, a path relative
to dub, or an absolute path, including a tilde-prefixed local path.
Unqualified relative paths are no longer allowed from the settings file,
as they make no sense for how dub invokes the compiler.

Merge pull request #1286 from dlang/short_single_objects ...

Use shortened object file names in single-file build mode.
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

Selectively import crc32Of from std.digest.crc

Fix compatibility with vibe.d < 0.8.2.

Rename Path to NativePath. ...

Matches the changes done in vibe.d 0.8.x and vibe-core.

Make the code base compatible with vibe-core. ...

This still generates lots of deprecation warnings, but successfully compiles with vibe-core, as well as with the old vibe-d:core package.

Remove FracSec

Mark all methods of Dependency safe or trusted.

Remove compatibility code for DMD frontends < 2.067.x.