Removing mut fields from vec.rs, at_vec.rs, str.rs, unstable.rs, and cell.rs.
Unstable didn't need transmute_mut after all.
Add Clone derivation for std::net::url types.
Add information about logging macros to the tutorial.

Closes #5699.
Fix compiletest on windows
typo fix: na -> an
Update tut. to not sound like I missed a section

The sentence "Remember that `(float, float)` is a tuple of two floats"
sounds like you've already read a section on tuples, but that section
comes later. Changing it to "Assuming that ..." makes it more about
taking the writer's word that the syntax is how tuples are defined.
auto merge of #5698 : Thiez/rust/de-mutfielding, r=pcwalton

This pull request removes some mut-fields from at_vec, str, vec, unstable, and cell. Sadly in case of Cell this required using either transmute_mut (2 instances) or changing the interface. I chose the former. Perhaps it would be a good idea to merge Cell and Option, and take that opportunity to change the interface to use '&mut self' instead of '&self' (which would enable removing the transmutations) for take and put_back.

r?
auto merge of #5701 : metajack/rust/net-url-clone, r=thestinger
One more typo: dubug -> debug
Simple typo fix
auto merge of #5704 : brson/rust/compiletest, r=luqmana
Remove a android hack
Decides main name by target
Fix fileinput test fail
auto merge of #5691 : ILyoan/rust/main_name, r=thestinger

Existing rust code decides main name by host environment of rustc.
I think it should be chosen by build target.

This patch is also removing one of the android hacks that is not necessary any longer(I think it was not necessary from the first).
auto merge of #5710 : ajuckel/rust/patch-1, r=luqmana

One word typo fix
doc: Rewrite task tutorial intro

It doesn't quite reflect reality
auto merge of #5703 : steveklabnik/rust/add_log_docs, r=thestinger

Closes #5699.
auto merge of #5707 : brettcannon/rust/patch-1, r=thestinger

The sentence "Remember that `(float, float)` is a tuple of two floats"
sounds like you've already read a section on tuples, but that section
comes later. Changing it to "Assuming that ..." makes it more about
taking the writer's word that the syntax is how tuples are defined.