Fix parameter handling of the "init" command.

Fix missing log argument.

Add --force switch for "dub run" and "dub build" and fix --rdmd.

Make sure the target binary gets deleted when the linker has failed.

Merge branch '0.9.20'

Update change log and bump version number.

Output a warning if no main source file is defined.

Add support for a "mainSourceFile" field. ...

The main source file is used as the root to access the whole package. This is important for dependency based building, such as with RDMD and for special build kinds, such as for a future unit test command. This also improves the robustness of "dub build --rdmd".

Main source files are automatically inferred as follows, if not explicitly given:
 1. search first in "source/", followed by "src/"
 2. take the first match of ("app.d", "main.d", "<pkgname>/main.d", "<pkgname>/<pkgname.d>") as the main file for the automatic "application" configuration
 3. take the first match of ("<pkgname>/all.d", "<pkgname>/package.d", "<pkgname>/<pkgname>.d") as the main file for the automatic "library" configuration

Let --annotate work for all commands.

Defer initialization code so that displaying help works immediately and without the danger to fail.

Revamp the command line interface with cleanly separated command implementations.

Fix Path.toNativeString() for empty paths (was missing the ending slash).

Add ".res" to the list of linker file extensions on Windows.

Fix unit test.

Fix duplicate file entries in generated VisualD projects. Fixes #168. ...

SourceFile.toHash was necessary for AAs to do anything useful and build==true files now have precedence over build==false files.

Code cosmetics.

Remove log output.

Avoid fetching the same package multiple times when sub packages are used.

Fix naming convention of PlacementLocation.

Only install pre-release versions with "dub upgrade --prerelease" if release versions are also available.

Don't warn about missing package.json in CWD when a different package was selected by name.

Don't upgrade unmanaged packages. Fixes #171. ...

Also renames Action.Type.get to fetch.

Fix --build=ddox.

Properly infer build options and target names when collecting package build settings without a configuration. ...

Also don't assert when a "targetType": "none" package doesn't have a target name.

Ability to generate dynlib projects with VisualD generator. ...

ie. <lib>2</lib>

Fix warning that for some reason only occurs on some systems...

Improve the Appender workaround.

Add workaround for corrupted Json values when using Appender.

Fix compiler error on DMD 2.063.2.

Let Json.checkType take an optional string to avoid compilation errors in the future.