Partially fix shared library build for LDC and skip tests for LDC/GDC. ...

Both compilers are not yet ready for shared library builds out of the box.

Use -fPIC for shared libraries compiled with LDC/GDC, too.

Change Build(Options/Requirements) to BitFlags.

Pass 'x86-64' arch to LDC instead of 'x86_64'

Fixed issue where static libraries would be generated instead of object files in singleFile build mode ...

+ Added object TargetType that is used during singleFile build mode

Use unique filenames for temporary files ...

Partial fix to #482

Fix error message with LDC

Fix output flags for compilers != dmd

Make prepareBuildSettings, extractBuildOptions and setTarget const

Removed trailing whitespace

Enable library targets for LDC compiler.

Output -l flags on the compiler command line after all source files. Fixes #281.

Merge branch 'dustmite'

Add simple support for --arch and LDC.

Add support for execution result callbacks in the build generator.

Rename BuildOptions.noBoundsChecks to noBoundsCheck to be consistent with BuildRequirements.requireBoundsCheck.

Rename some BuildOptions to avoid D keywords.

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.

Fix handling of lib flags on Windows for GDC/LDC.

fix gdc/ldc build options

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

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

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

Improve adherence to code conventions.

Fix handling of -enable-inlining, -d-debug, -d-version and -disable-boundscheck arguments in the LdcCompiler class. Supposedly fixes #86, but not tested, yet.

Introduce TargetType.none, fix handling of non-target project's dependencies and avoid continuous reinstalls of referenced sub-packages.

Fix LDC linker flag specification and add workaround for conflicting object file names.

Use -d-debug instead of -debug for LDC.

Attempt to fix handling of "-Wl" flags returned by "pkg-config".

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