Deprecate the "visuald-combined" generator.

Reimplement the VisualD generator based on the new target generation code and fix link dependencies for static libraries.

Only treat "main.d" and "<packname>/main.d" as "mainSourceFile" for library targets.

Fix the configuration resolution algorithm. ...

The initial graph of the old algorithm contained edges to configurations that
couldn't themselves resolve all dependencies. These are now skipped, so that
only valid sub graphs exist. This avoids bogus "Could not resolve configuration
for package X" errors.

Fix version(Linux) -> version(linux) - gotta love inconsistent naming...

Properly saving the journal's filename of the package description.

Keeping track of the saved json file in the journal and some smaller changes.

Make "dub.json" the primary choice for a package description and handle "package.json" as a fallback.

Subpackages, which are defined external to the main package.json can be fetched from the registry. Eventually, the dependencies of all referenced packages will be fulfilled, but this is done by a hack where the metadata of the external package is inferred as having no additional dependencies. When the package is then fetched the state is re-evaluated and possible new dependencies will be resolved.

Reverting unwanted commit.

Revert "With discoverable subpackages, the examples are named like their folder." ...

This reverts commit 440089b.

Automatic discovery is disabled.

When a package having externally defined subpackages is installed, they work. Currently not tested with the registry.

With discoverable subpackages, the examples are named like their folder. ...

When it is allowed to name these differently, the package id would be rather strange for the normal usecase (e.g. a dependency on dub/examples/app/app would be required)

Automatic discovery of sub-packages added to package manager.

Inside of the PackageManager, change type of m_packages from Package[][string] to Package[], as there is no need for an associative array, currently.

Fixed typos.

Apply the platform specific build settings to all targets. Fixes #201. Fixes #204.

Don't include package.d modules for "dub test". See #198.

Use --no-as-needed only in Linux (OSX's LLVM based tool chain doesn't support it).

Determine proper module name for "package.d" files and "dub test". Fixes #198.

Add --no-as-needed to avoid linker errors with new GCC versions used as the linker front end. See #199.

Put linker flags (including "libs") after linker "sourceFiles". See #199. ...

Supposedly fixes an issue where a dependency that was build as a static library cannot access symbols of an external library that it needs, because the external library is passed to the linker before the dependency itself.

Avoid "linking" static library targets against dependencies. Fixes #199.

Remove log noise.

Fix build settings used for dependencies that are referenced multiple times and remove the Mono-D generator.

Fix compiler errors on DMD 2.063.2.

Fix computation of build settings necessary for linking to library dependencies.

Implement a first version of a proper build ID computation. ...

Currently, the build ID is built from a few options that are not strictly necessary to be included (build flags and options) - it would be sufficient to just include the build settings introduced by the selected build type (and would reduce the number of build cache folders).

Improve error message when removing a cached package fails due to a missing installation journal.

Implement individual building of dependencies.