Implement BigInt and BigUint.
Move BigUint and BigDIgit to std::bigint.
Convert std::bigint to explicit self.
Impl Zero, One of BigInt, BigUint
Convert @[BigDigit] to ~[BigDigit]
Enhance auto_encode to take number of struct fields

emit_struct and read_struct takes an additional len:uint parameter which tells
us how many fields the struct we are working on has.

This is required to implement an Encoder for the msgpack [1] serialization
format. To serialize a struct with msgpack you have to use arrays and the size
of the array has to be know before each of the elements are written out. JSON
as an example doesn't have this problem as it uses '[' and ']' delimiters for
arrays.

[1]: www.msgpack.org
Remove spurious semicolons at the end of macro_rules! definitions.
When an import fails to resolve, make the error message say
which import it actually was. This makes debugging imports
like: use aa::{x, y, z} easier (for issue #2914).
Fix the build by removing trailing whitespace.
Simplify idents_to_str and use it in more places.
reset LinearMap.size when expanding buckets
doc: make small corrections to tutorial
Merge pull request #4317 from apasel422/tutorial-fix

doc: make small corrections to tutorial
Merge pull request #4311 from FranklinChen/fix-macro-tutorial

Remove semicolons at the end of macro_rules! definitions that cause compile failure
Add Franklin Chen to AUTHORS
Merge pull request #4312 from Dretch/issue-2914

Work towards fixing issue #2914
rt: Remove dead code from schedule_task()
doc: Fix some typos in the tutorial and reference manual
Merge pull request #4323 from cpeterso/cpeterso-schedule-task

rt: Remove dead code from schedule_task()
Merge pull request #4322 from cpeterso/incoming-doc-typos

doc: Fix some typos in the tutorial and reference manual