Fix clippy warnings.

[dineshadepu]

The following warnings are omitted

1. Redundant field names
2. Constants by default have a 'static' life time
3. Redundant pattern matching
4. match statements by dereferencing
5. Using clone on copy type
6. Inclusive ranges
7. Manual copying loops
8. Dedicated clone methods

[dineshadepu]

There are some warnings such as

warning: the loop variable `i` is only used to index `slc`.
    --> src/lib.rs:1340:22
     |
1340 |             for i in 0..slc.len() {
     |                      ^^^^^^^^^^^^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
help: consider using an iterator
     |
1340 |             for <item> in &mut slc {
     |                 ^^^^^^    ^^^^^^^^

I tried to solve this, but I get into copy or clone not implemented errors.

And I also didn't change the fields with single char. The warning looks like

warning: 6th binding whose name is just one char
   --> src/linalg/impl_linalg.rs:508:17
    |
508 |         let mut j = 0;

I felt it is meaning full.

And also I haven't fixed the specific error catching, the warning looks like

warning: Err(_) will match all errors, maybe not a good idea
   --> src/impl_constructors.rs:140:13
    |
140 |             Err(_) => panic!(
    |             ^^^^^^
...
243 |         let _ = size_of_shape_checked_unwrap!(&shape.dim);
    |                 ----------------------------------------- in this macro invocation
    |
    = note: to remove this warning, match each error separately or use unreachable macro
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#match_wild_err_arm

I am looking into the code, once I get the error handling and error types defined in ndarray I will try to change that to specific error types if needed.

[LukeMathWalker]

Thanks for working on this @dineshadepu!
Let us know when you think it's a good time to review this PR 💪

[dineshadepu]

Yes, it ready to review.

@LukeMathWalker

[LukeMathWalker]

I'd like to have clippy in the CI pipeline: it would be nice to have a reference that every contributor on a PR can look at to see linter warnings. Ideally the build should only fail on errors, not warnings (let's start with a bit of slack).
I have cloned your branch locally @dineshadepu and I can see a bunch of clippy errors:

• this loop never actually loops
• you are implementing Hash explicitly but have derived PartialEq
• you are deriving Hash but have implemented PartialEq explicitly
• use of #[inline] on trait method contiguous_stride which has no body
• the since field must contain a semver-compliant version

To add Clippy to our CI pipeline, we should either resolve these errors or disable Clippy for those error classes/functions/methods.
Similarly, if there are warnings that we do not plan to address, we should disable them, either locally or globally.

[alex179ohm]

I made some pull-requests on these errors but they are all referenced to the #642 issue (I just looked for clippy on issue's search bar and the 642 has been the first open issue coming out :))
Maybe the coming pull-requests should be referenced to this issue?
there is just one error unsolved and it is the semver-compliant related to the since field (does the 0.13 release exist?)