libcore/to_bytes.rs: add IterBytes impls for pairs and triples
Update src/README.txt

updated the new names of source directories - librustc, libcargo, librusti, librustdoc, libfuzzer
Add more standard c lib llvm intrinsics.
librustc: Make the Drop trait use explicit self
test: Add a test for generic objects. r=test-only
test: Add a test that function argument patterns take in the expected type. r=test-only
test: Fix broken resource-cycle.rs. r=tinderbox
libsyntax: Remove the "by-mutable-ref" obsolete syntax error; it blocks useful function argument patterns. Add a test for the latter. r=brson
Allow `macro_rules!` macros to expand to expressions or items.
Grammaticalinate an error message.
Make it possible to invoke item macros without passing identifier arguments.
Allow for macros to occur in statement position.
Make it possible to expand stmt macros.
Use `biased_match!` to avoid over-deep indentation in expand.rs.
Allow the expansion of old-style expr macros in stmt position.
No longer parse the delimiters of the RHS of a macro as part of the expansion.
Allow parsing of macros in statement position.
Make the parser handle stmt macros that might be exprs at the end of blocks.
Distinguish `stmt_mac`s that are followed by semicolons and those that aren't.
Forbid item macros from occuring where statement macros might occur, and allow item macros to look like statement/expr macros.