Fix detection of already visited nodes in DependencyResolver. See #280. ...

Fixes a stack overflow for package graphs with cycles.

Properly support path based version selections.

Let "*" match any version or branch. Fixes #151.

Let Dependency.toString() also contain the optional/path properties. ...

versionString is changed into a public property to support the use cases where only the version range is expected.

Fix resolution of optional and path based dependencies.

Add command line interface for managing package overrides.

Move DependencyResolver to its own module and reorder Version<->Dependency.

Fix 64-bit compilation.

Compile fix for DMD 2.064.

Implement a new dependency resolution algorithm with support for selections. ...

The new algorithm is completely rewritten to be able to find any valid combination of dependencies/versions. The old one could error out in cases where a valid dependency tree could have been built. Now the current selections are also taken into account when invoking without UpdateOptions.upgrade.

Some side changes:
 - Comparing branch versions is allowed now to enable sorting the full set of versions of a package
 - DependencyGraph and RequestedDependency have been removed

Build fix.

Fixing 'dub fetch xyz --version=a.b.c', the latest version was fetched instead of the specified. ...

The problem was that Dependency("1.0.0") != Dependency("==1.0.0") or Dependency(Version("1.0.0")). Similar to the branches, not specifying a comparison operator assumes identical version required.

Preparing dub select command. dub select will select the currently used versions and write them to a file, so that dub can later use this information to rebuild this exact state. This will also be used to override dependencies with either branch versions or not matching versions (to resolve conflicts). (All of this if to be implemented). ...

Other changes:
- Added Version.UNKNOWN, which could be later used for undetermined package versions instead of ~master.
- Added Dependency to/fromJson.
- Added Dependency alias "*" for ">=0.0.0".

Following rubygems version specification for approximate version more closely.

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

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.

Add assertion message.

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

Add unit tests for "==~branch" and changed the semantics of Version.isBranch. ...

Version.isBranch now also returns true for "~master".

Fix parsing of "==~branch" style dependency version specifiers.

Little doc clarification.

Fix triggering an enforcement for Version.INVALID.

The externally defined sub-packages don't have the name declared in the base package. This eliminates the double definition of a sub-packages name.

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

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

Switch version comparison to use the more efficient implementation in dub.semver.

Fix unit test for DependencyGraph.

Use the exact dependencies instead of base packages for missing dependency resolution. Fixes #140.

Move dub.utils to dub.internal.utils and update copyright dates.