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

Merge pull request #1308 from tofuninja/patch-1 ...

Fix sublime text generator file regex
merged-on-behalf-of: Sönke Ludwig <s-ludwig@users.noreply.github.com>

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.

Merge pull request #1307 from wilzbach/bump-vibed ...

Bump vibe-d to 0.8.3-alpha.1
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

Bump vibe-d to 0.8.3-alpha.1 ...

vibe.d 0.8.3 will only be compatible with DMD >= 2.072, hence the Travis
build script was updated too.

Merge pull request #1208 from joakim-noah/next ...

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

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>

Merge pull request #1283 from dlang/vibe_core_compatibility ...

Make the code compatible with vibe-core
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

Selectively import crc32Of from std.digest.crc

Upgrade dependencies.

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.

Merge pull request #1295 from wilzbach/kill-fracsec ...

Remove FracSec

Remove FracSec

Merge pull request #1294 from dlang/remove_compatibility_code ...

[trivial] Mark all methods of Dependency safe or trusted.
merged-on-behalf-of: Sebastian Wilzbach <sebi.wilzbach@gmail.com>

Mark all methods of Dependency safe or trusted.

Merge pull request #1293 from dlang/remove_compatibility_code ...

[trivial] Remove compatibility code for DMD frontends < 2.067.x.

Remove compatibility code for DMD frontends < 2.067.x.

Merge pull request #1292 from dlang/optimize_dep_resolution ...

Optimize dependency resolution and add a hard execution limit

Drop CI support for the DMD 2.066.1 frontend.

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.