Fix --build=ddox.

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

ie. <lib>2</lib>

The previous OSX fix is also needed for Linux, so change to version(Posix).

Fix "dub run" on OS X. ...

spawnProcess on OS X requires "./" to be appended for starting processes in the CWD.

Don't emit -fPIC for DMD on Windows. Fixes #166.

Add diagnostic message for the target copy operation of the cached build generator.

When doing separate compile/link building, pass (.o/.a/.ao/.dylib/.obj) files to the linker command line. ...

This was already done for .lib files.

Perform target setup when performing a cached build. Fixes #159.

Avoid duplicate "package.json" entries in generated VisualD projects.

Integrate the rdmd generator into the build generator and start to implement build caching. ...

The basic directory structure, as outlined in https://github.com/rejectedsoftware/dub/wiki/Separate-compilation-and-caching-of-dependencies has been implemented.

Still missing:

 - Dependencies are not built separately
 - The hash part of the build directory is not taking into account any build properties right now

Import and string import files are now added to generated VisualD projects and "dub describe".

Fix running executables that are not built in the CWD and create the target path if necessary.

Build to a temporary folder only if necessary. Fixes #82.

Fix "dub --build=ddox" and let it open the docs in the system browser automatically.

Remove dub.internal.std.process compatibility code as it doesn't support browse() and the compile status on older DMD versions isn't tracked anyway.

Make "dub build --build=ddox" work for any target type and avoid including dependencies in the documentation. Fixes #142.

Issue -shared and -fPIC when building shared libraries with DMD. Fixes #138.

Make all paths issued by the build generator relative to work around issue #130.

Remove the now redundant GeneratorSettings.compilerBinary field.

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

Let the individual compiler classes handle passing arguments to the compiler. Fixes #86.

Name response file dub-build.rsp instead of .dmd-response-file.txt and only quote arguments if needed. ...

LDC seems to dislike quotes in response files (errors out with: Error: unrecognized file extension d"). Now at least builds with no spaces should work fine. See also #86.

typo in comment

Avoid multiple identical package.json inclusion in combined VisualD project generation when using sub-packages.

Moved Journal into packagemanager.d. Removed Project.writeMetadata as it is not used. Documentation typos and updates.

[visuald generator] When generating a combined VisualD project file, generates nicer <Folder>. ...

Each source file structurePath is now relative to its own package.
                    Note: all sub-packages are conflated to the same <Folder>, because it seems VisualD can't display folder names with a colon.

Avoid redundant dependencies and .lib dependencies in generated VisualD projects if possible. ...

Any redundant dependency can cause "multiple definition" linker errors.

Generalize common compiler switches in the form of a BuildOptions enum. ...

Related changes:
 - translation of DMD compiler switches to other compilers is generalized
 - application of build requirements is generalized
 - added support for debug versions
 - supporting almost all compiler settings for generated VisualD projects now

Avoid specifying compiler flags that are already handled by special fields in the VisualD generator. See rejectedsoftware/vibe.d#269.

Add support for customized build types ("buildTypes"). Fixes #78. ...

Also changes the way the $DFLAGS environment variable works: passing --build=xyz will now cause DFLAGS to be ignored.