rm ancient error for lowercase kinds

3 of these kinds no longer even exist in the CamelCase form
remove `copy` as a keyword
test: Disable morestack tests

The new scheduler does not yet implement split stacks
extra: Remove dbg module and rt support code

This stuff is ancient, unused, and tied to oldsched
register snapshots.
auto merge of #8177 : graydon/rust/2013-07-31-register-new-snapshots, r=thestinger

r? someone
make `in` and `foreach` get treated as keywords
convert `pure` to a reserved keyword
auto merge of #8162 : thestinger/rust/no-copy, r=brson
auto merge of #8149 : omasanori/rust/cleanup, r=alexcrichton

Fixed a warning.
rc: from_{owned,const} -> from_{send,freeze}
Resolve globals having different addresses across crates

* All globals marked as `pub` won't have the `internal` linkage type set
* All global references across crates are forced to use the address of the
  global in the other crate via an external reference.
migrate many `for` loops to `foreach`
auto merge of #8184 : thestinger/rust/retreat, r=huonw
auto merge of #8155 : stepancheg/rust/unit-zero, r=alexcrichton
auto merge of #8158 : bblum/rust/task-cleanup, r=brson

r? @brson
syntax: implement cfg!() which evaluates to true/false where #[cfg] would keep/remove.

Example:

   if cfg!(test) {
      calculation_to_run_only_when_testing();
   }
auto merge of #8164 : brson/rust/noportset, r=pcwalton

...haredChan.
std: Use `do` blocks instead of `for` with .iter_bytes()
extra: Use `do` instead of `for` in extra::iter