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.

Defer error message generation to the end of the dependency resolution process.

Put a hard limit in the number of dependency resolution iterations. ...

This avoids the process getting stuck in the resolution phase "indefinitely", so that for example CI runs don't get stuck anymore. It also communicates the problem and potential resolutions more clearly. If the DUB_NO_RESOLVE_LIMIT environment variable is set, the resolution process will run without this limit.

Small optimizations in DependencyResolver.

Cache the result of DependencyVersionResolver.getChildren.

Avoid GC allocations in DependencyVersionResolver.getChildren.

Optimize Dependency.merge. ...

Reduces the amount of version comparisons.

Optimize Dependency.toHash/matchesAny.

Add pure/nogc annotations to the SemVer module.

Optimization: avoid UTF decoding in the semver module. ...

SemVer operates on ASCII only, so there is no need to perform any decoding.

Don't weaken the selected log level for "dub describe".

Merge pull request #1193 from dlang/registry_skip_configured ...

Add SkipPackageSuppliers.configured and fix unit test.
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

Improve command line documentation for --skip-registry.

Add SkipPackageSuppliers.configured and fix unit test. ...

With only .all and .standard, an intermediate option was missing to make the unit test pass on systems with additional registries configured in the DUB configuration.