MergeSort

• Add example-mergesort.cc for fast parallel sorting.
• Improve explanation of the manual mode in chapter 3.

Thread pool

Thread pool added (section 2.2 in README.md)

Clang compatibility added.

Lazy can now be compiled with both gcc and clang.

Improve Lazy::Sequence

Lazy::Sequence now works with std::ranges::views if you use C++20 compiler.
Example:

    constexpr int N = 10;
    auto even = [](auto i) { return 0 == i % 2; };
    auto square = [](auto i) { return i * i; };
    auto lseq = Lazy::Sequence{N};

    for (auto i : lseq | std::views::filter(even) | std::views::transform(square)) {
        std::cout << i << ' ';
    }
   std::cout << "\n";

Output: 0 4 16 36 64

CMake integration

CMake integration by FriendlyAnon.

Optimize parallel running of void functions and add Lazy::Sequence range container

Vector in, vector out - mode is now faster if the return type of the function is void. Dummy return type is not needed anymore.
Also Lazy::Sequence range container has been added.
See README.md and example 2.6 in example-2.cc for further details.

Array output improvements

The issue where the output type of Lazy::runForAll(...) was sometimes std::vector when it should be std:array has been fixed.

First release

Includes the functionality of the three use cases described in README.md.