Aliases for classes used by clients to reduce templating clutter

[AmroAlJundi]

SparseBase is highly templated to allow users maximum freedom when defining their objects. However, with all this templating, code starts becoming cluttered and hard to understand. For this reason, we will define new aliases for client-facing classes and functions in which templated arguments are part of the alias name. For example, instead of the code in Snippet A below, the user can use Snippet B:

// Snippet A: non-aliased code is cluttered
CSR<unsigned int, unsigned int, unsigned int> csr;

// Snippet B: aliased code gets rid of the clutter
CSR_iii csr;

In the current model of using the library, the only part of the API that the client will have to use is a) functions in Bases and b) Format classes. The former category, with the exception of IOBase, does not require template arguments as they are deduced from the input. The latter category requires explicit template arguments. Therefore, we will add aliases for Format classes and IOBase functions only.

Google's C++ Style Guide has some details on good aliasing behavior.