test fallback mirror usage on server errors

allow to add fallbacks to custom registry for testing purposes

unify retry counts to 3

fix retry on http status error ...

- silent http status errors (e.g. 502) should be responsible
  for most "corrupted" zip packages

restrict zip exception handler to specific unpack statement

Don't break out of the retry loop for ZipExceptions - fixes #1336

update version to v1.7.1

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

download timeouts ...

- 8s by default
- only for curl atm.

update version to v1.7.0

update version to v1.7.0-rc.1

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

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.