Implement Zero for unit
Remove unused variables.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Give tasks useful names. #2891
Move atomically to unstable::sync, and document what it actually does. Close #7872.
test: add more codegen tests, add copyright headers to all.
rm ancient error for lowercase kinds

3 of these kinds no longer even exist in the CamelCase form
remove `copy` as a keyword
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}
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
auto merge of #8164 : brson/rust/noportset, r=pcwalton

...haredChan.
auto merge of #8165 : graydon/rust/2013-07-31-new-codegen-tests, r=brson

r? @pcwalton or someone