Implemented sub packages. Fixes #67. ...

Sub packages are referenced using the syntax "main-package-name:sub-package-name" and can be defined using a "subPackages" field or by putting package.json files in subdirectories of the main package.

fixed uninstallation

Made "dependencies" a per-configuration setting instead of a purely global setting.

Add support for DUBPATH and "add-path" + change the default installation location to the DUB user path. Fixes #64. ...

This change allows to specify a number of directories in addition to the system and user DUB package directories to search for local packages.

Full list of changes:

 - Add support for the DUBPATH environment variable (a (semi-)colon separated list of paths)
 - Add support for "dub add-path" and "dub remove-path" to add static search paths
 - The branch of local packages with no "version" field in their package.json is now inferred using "git rev-parse"
 - The structure of the user/system package directories is changed from "packages/<packname>/<packver>" to "packages/<packname>-<packver>"
 - There is no project local package directory (".dub/packages") anymore - packages are instead installed to the user package directory by default
 - Upgrading and uninstallation is partially broken in this commit - will be fixed later

Deprecate "relaxProperties", remove the default -property switch and warn about using them. Fixes #73.

Change the file dictionary to a file list for "dub describe"'s output.

Implement a first version of "dub describe".

Implement the "noDefaultFlags" build requirement. Fixes #68.

Write the "optional" field out as bool instead of string.

Fix compilation with latest LDC.

Added "optional" dependency flag.

Move all source files outside of "dub" to "dub/internal".

Added very simple hashing of a package.

Implemented "buildRequirements" as a way to avoid certain compiler settings for specific code bases. ...

See also #61.

Make configurations inherit the global target type by default. ...

See also #59.

Support "-ddoxFilterArgs" field to control how --build=ddox filters documentation entities.

Improve output of the dflags warning message. Fixes #54.

Output warning if DUB controlled compiler flags are specified in package.json. Fixes #37.

Configurations do not override the global targetName/targetPath if non-was specified in the configuration. Fixes #48.

TODO "optimize": Done ...

Suffix checking easier and more efficient.

I also fixed some unittests some others that triggered I disabled (Soenke please review).

Fixed source file search. ...

Changed "*d" to "*.d", "*d" also triggers for example ".md".

Fix target settings for dependencies in the Visual-D generator.

Fixed recursive configuration deduction and improved error messages for invalid package.json files.

Added a "subConfigurations" field and implemented proper configuration selection for dependencies.

Added "targetName" and "targetPath" build settings and some fixes. ...

Other changes:
 - Made the comparison for "excludedSourceFiles" path format agnostic
 - Fixed the output directory for the VisualD generator
 - Removed the "binaryPath" global setting (which was undocumented up to now)

See also #26 and #29.

"sourcePaths" is now a build setting instead of a global field.

Implemented the "excludedSourceFiles" build setting.

Improved configuration selection for dependencies. ...

Still missing a way to select a specific configuration for each dependency.

Change the way configurations are specified. ...

Configurations are now given as a list instead of a map and the defaultConfiguration field was removed. Instead, the first configuration that matches the target type and platform is chosen.

Added the notion of a target type.