(WIP) Setup Appveyor

[UK992]

CC @upsuper @emilio

Issues:

• test/expectations fails at:

error[E0512]: transmute called with differently sized types: u64 (64 bits) to i32 (32 bits)
  --> tests\bitfield_align_2.rs:78:18
   |
78 |         unsafe { ::std::mem::transmute(val as u64) }
   |                  ^^^^^^^^^^^^^^^^^^^^^ transmuting between 64 bits and 32 bits

• MSVC with LLVM 3.9: many tests fails
• 32-bit builds: many tests fails

Appveyor build: https://ci.appveyor.com/project/UK992/rust-bindgen/build/1.0.62

[upsuper]

Hmmm... I wasn't aware of tests inside tests/expectations... and yeah, it fails for the same reason locally, will investigate.

32bit builds seem to be much broken at present...

Should we probably merge this and fix the failures latter?

[fitzgen]

A lot of the test scripts seems like copy/paste of functionality we have in existing scripts. Is the reason they can't be shared because the existing scripts are bash? If so, we should file a follow up to port them all to python or something. I'd really like to avoid duplicating them, as it will make changing them much more difficult.

Should we probably merge this and fix the failures latter?

Ideally mark them as "allow failures" somehow, and then when we fix them, remove that annotation. Does appveyor allow this kind of thing?

[fitzgen]

@UK992 would you mind rebasing and squashing this PR? Then we can land it and address the above concerns as follow ups.

[fitzgen]

/me grumbles that appveyor's results are impossible to read if one is red-green colorblind

[UK992]

done.

[fitzgen]

Thanks @UK992! Very appreciated :)