remove DOCS from default target and druntime.zip

- These are the raw b&w ddoc html files that nobody uses.

- The distributed druntime docs are generated
  by dlang.org (through the doc target).
move -version=CoreDdoc to DDOCFLAGS

- DOCFMT is typically overriden when calling
  the makefile.
fixup #674 - should test .length instead of .ptr
Fix Issue 4483 - foreach over string or wstring, where element type not specified

core.demangle does not support Unicode and iterates over ASCII only.
core.time: Add type, function and conversion cheat sheet to module DDoc
core.time: Mention std.conv.to in opCast documentation
Merge pull request #711 from CyberShadow/core-time-clarifications

core.time: Conversions and documentation
Add internal documentation about Fibers
[ARM] Implement Fibers
Merge pull request #713 from jpf91/arm-3

[ARM] implement fibers & Add internal Fiber documentation
no need to GC scan the .rodata segment

- Also _deh_end will have to live in .data for PIC code
  (Bugzilla 11171), so it can't be used as end of .rodata.
Replace naked Read-Modify-Write ops on shared values which will be banned.
add unittest for finalization during library unload
finalize objects whose shared library is about to be unloaded
Merge pull request #714 from AndrejMitrovic/Prepare3672

Replace naked Read-Modify-Write ops on shared values which will be banned.
Remove uses of the comma operator
Merge pull request #716 from yebblies/commaop

[trivial] Remove uses of the comma operator
lazier generation of stack traces
the throwing function was left out!
Revert "the throwing function was left out!"

Oops, turns out the default handler leaves it out too so this was
correct the first time.

This reverts commit f715ecdc335127508b3eed36c20d320f388a375e.