Matrix Contiguity Lacks Reliability; Update to improve this

[BigUglySpider]

While the construction of a Matrix as two EmuMath Vectors is useful in some rights, it results in a compiler-specific dependency: One compiler may create a contiguous matrix, whereas another compiler will make the same matrix non-contiguous due to padding. The same compiler could also result in different contiguity dependent on the target build platform.

This issue proposes the following:

• [x] Store Matrix data as a contiguous, flattened array
  • This makes contiguity a guarantee, instead of a compile-time conditional
• [x] Maintain the same access interface
• [x] Maintain a similar GetColumn/GetRow/etc... interface
  • Direct reference returns will no longer be possible without dangerous behaviour
  • All returns will remain defaulting to reference output
    • The key difference with this is that the output reference will always be a Vector of references, instead of a reference to a Vector. This introduces extra overhead compared to the direct reference return, but this is a use case that is likely not especially common, and in cases where it is common it is likely possible to cache a reference Vector for repeated uses (after all, the references to one specific Vector's elements will never change).

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Additional checklist added after initial proposal

• [x] Remove dead code references
• [x] Update code for new interface

[BigUglySpider]

As of commit 90e47c67a45feb5cf378c95336a392245618f1be data is stored contiguously within a Matrix.

Work is still being done to accommodate for these changes, such as column/row access.

As of this comment, all construction methods have been rebuilt and optimised to defer construction to the underlying storage to reduce code duplication and assist the compiler with RVO.

[BigUglySpider]

As of commit e5f1d1ff9f62f08dc2585a36e12527ea813679dd (f5395e17f71356bbc7bf8c0bbb2b152521d204f5 for diff), all items in this issue's proposal have been implemented.

This issue will be closed after a final cleanup phase, which aims to clean up references to dead code, and update outdated expectations of Matrix behaviour.

[BigUglySpider]

As of 0c0800af7fcc2b8a84db0de42a75233bdb05a76d, this issue is resolved, with pull request #46.