Tag version 0.9.21.

Merge branch '0.9.21'

Following rubygems version specification for approximate version more closely.

Fix compilation on 64-bit systems.

Improve wording.

Prepend an explicit .\ when executing executables in relative paths on Windows, too. ...

Sometimes the wrong executable was picked up for "dub run" or "dub test".

Implemented ~>1.3.5 version specifier similar to what rubygems are doing.

Support --combined and --force flags for "dub test". Fixes #247.

Don't downward inherit Have_* versions and only partially string import paths. ...

This change allows library builds to be reused for multiple dependees in most situations. String import paths are now only downwards inherited for packages that already have string import paths defined.

Add the target platform to the .dub/build/* cache folders. ...

Enables sharing of the same package folders for different platforms.

Fix typo.

Add --force-remove switch and reimplement PackageManager.remove. ...

remove() now first checks for untracked files and leaves the package untouched if it finds some and no force_remove is supplied. This means that after the user gets an error concerning untracked files, it's possible to rerun dub with --force-remove to remove the package cleanly.

Warn when using -m32/-m64 directly.

Improve error messages for errors during package removal.

Improve error message in case of missing packages.

Fix unit tests to use lower case package names.

Change Dependency.toString to output "x.y.z" instead of "==x.y.z" for exact versions.

Fix triggering an assertion when storing dependencies in advanced format. ...

The code was assuming that such dependencies had always exact versions, which is of course not always true (it should, however, be true for dependencies with a "path" field).

Print a more descriptive error message when PackageManager.getTemporaryPackage fails.

Fix condition for testing if a package description exists.

Add assertion message.

Make sure that conflicting dependencies result in a proper error message.

Add proper documentation for the "dub test" command. Fixes #83.

Only insert packages belonging to the same target into TargetInfo.packages.

Output errors the occur while fetching package information as diagnostic output. See also #236.

Ensure a deterministic file order when passing source files to the compiler. ...

This should avoid "random" triggering of compiler bugs that depend on the order of source files. See also rejectedsoftware/vibe.d#493.

Always use lower case package names internally, regardless of the package description.

Add simple support for --arch and LDC.

Add -defaultlib=x to the flags that need to be passed to the separate linking stage for DMD.

Silence the "Checking dependencies" message on startup. Fixes #221.