Fix LICENSE file.

- DDMD uses Boost Software License
- Update LDC copyright to 2016

This fixes issue #1322.

(cherry picked from commit 3c12511)

Author: redstar

LICENSE

@@ -5,9 +5,9 @@ LDC is released under the "three-clause BSD" LDC license reproduced below, with
 the following exceptions:
 
 Compiler (bin/ in binary packages):
- - LDC uses the DMD frontend (dmd/* and dmd2/* in source code distributions),
+ - LDC uses the DMD frontend (ddmd/* in source code distributions),
    which was originally written by Walter Bright and is released under the
-   Artistic license or the GPL version 1. LDMD (driver/ldmd.cpp) and the RTTI
+   Boost Software License - Version 1.0. LDMD (driver/ldmd.cpp) and the RTTI
    handling code (gen/typinf.cpp) are also partly derived from DMD.
 
  - LDC incorporates code (gen/asmstmt.cpp and gen/asm-*.h) originally written
@@ -31,7 +31,7 @@ Full license texts
 
 -- LDC license -----------------------------------------------------------------
 
-Copyright (c) 2007-2012 LDC Team.
+Copyright (c) 2007-2016 LDC Team.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
@@ -58,6 +58,12 @@ ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
+-- DMD license -----------------------------------------------------------------
+
+Copyright (c) 1999-2016 by Digital Mars written by Walter Bright.
+
+DMD is released under the terms of the Boost Software License - Version 1.0.
+
 
 -- Runtime library license -----------------------------------------------------
 
@@ -86,13 +92,12 @@ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
 
 
-
 -- LLVM license ----------------------------------------------------------------
 
 University of Illinois/NCSA
 Open Source License
 
-Copyright (c) 2003-2012 University of Illinois at Urbana-Champaign.
+Copyright (c) 2003-2016 University of Illinois at Urbana-Champaign.
 All rights reserved.
 
 Developed by:
@@ -132,14 +137,8 @@ SOFTWARE.
 
 
 
--- DMD license -----------------------------------------------------------------
-
-Copyright (c) 1999-2012 by Digital Mars written by Walter Bright.
+-- License of GDC artefacts ---------------------------------------------------
 
-DMD is released under the terms of the Artistic license or the GNU General
-Public License, version 1.
-
---
                          The "Artistic License"
 
                                 Preamble
@@ -512,7 +511,7 @@ That's all there is to it!
 
 -- libconfig license -----------------------------------------------------------
 
-Copyright (C) 2005-2010  Mark A Lindner
+Copyright (C) 2005-2016  Mark A Lindner
 
 --