Use u32 for index
Move benchmarks to cargo directory benches/
Use language: rust in .travis.yml
Add dimension helper functions d1, d2, d3
Move Si and do_slices into dimension.rs
Array: Support {:e} and {:E} formatting.
Array: Format the array as a single line in alternate style.
Merge branch 'u32-index'

* u32-index:
  Add dimension helper functions d1, d2, d3
  Use language: rust in .travis.yml
  Move benchmarks to cargo directory benches/
  Use u32 for index
Port tests/array.rs
Bug fixes en masse for u32 indexes
All tests pass for u32 indexes
Add ixrange as synonym for range::<Ix>
Array: documentation about index type.
Enable using Complex<F> in linalg by default