fix Issue 9198 - Vararg functions don't respect IFTI rules
fix Issue 6905 - ref acts as auto ref when return type is missing
Fixes Issue 8787 - Better diagnostic on non-final interface function with a body.
drop 'www.' from dlang.org urls
switch ddoc references from digitalmars to dlang
fix up file header comment

1) drop obsolete links to dsource
2) drop path to backendlicense.txt
3) update readme.txt to point to dlang.org
fix Issue 9254 - ICE on invalid foreach aggregate

ForeachRangeStatement and WhileStatement are basically replaced into ForStatement in semantic phase.
If any error occurs, they will be left as is, however.

Therefor, `assert(0)` in blockExit, usesEH, comeFrom have the potential to be invoked.
detab test/runnable/testswitch.d
Add -w option in PERMUTE_ARGS, and fix test cases.

As far as I see, these changes does not affect to the things which are actually tested.
fix Issue 9263 - statement is not reachable when statement is reachable
Merge pull request #1431 from 9rnsr/fix9263

Issue 9263 - statement is not reachable when statement is reachable
Trivial cleanup: Consistently use the CPP_MANGLE macro.
Merge pull request #1432 from klickverbot/use-cpp-mangle

Trivial cleanup: Consistently use the CPP_MANGLE macro.
Merge pull request #1430 from 9rnsr/fix9254

Issue 9254 - ICE on invalid foreach aggregate
Fixes Issue 9250 - Wrong line number in assignment diagnostic
Merge pull request #1433 from AndrejMitrovic/Fix9250_2

Issue 9250 - Wrong line number in assignment diagnostic
no more calls to __DBLULLNG
eliminate need for __DBLULNG
eliminate need for __LDBLULLNG
Merge branch 'master' of github.com:D-Programming-Language/dmd