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.

Implemented the "excludedSourceFiles" build setting.

Added the notion of a target type.

The internal package representation is now JSON agnostic + streamlined configuration and dependency handling. ...

Still missing for the new configuration handling:
 - A way to select which configuration to use for a dependency (instead of the default "library")
 - New method to define a default configuration per platform and mode (application/library)

Implemented pre/post commands and --build=ddox + support "sourceFiles". ...

Other fixes:
 - fixed class Dub to work with other path than cwd
 - "files" has been deprecated in favor of "sourceFiles"
 - --build=docs also works now
 - Changed the way build flags are parsed (instead of checking every possible field for existence, all fields are iterated and their name is matched)

Renamed all the "vibe" package to "vibecompat" to avoid conflicts.

Added rudimentary support for the --arch= option and moved build type flag generation to a common place.

Added a new "build" generator that directly invokes the compiler. ...

This generator supports all compilers in contrast to the rdmd based one and will later be the default.

Added LDC support and improved compiler name maching (e.g. gdc-2.061 is now matched with gdc)

Also added support for gdmd and ldmd

Implemented basic multi-compiler support (with only a dmd implementation right now).