Use std::make_shared to allocate shared ptrs, instead of std::shared_ptr constructors

[ferdnyc]

std::make_shared does in a single allocation what the constructors for std::shared_ptr usually take at least 2 allocations to do.

//
// This PR replaces instances of shared-pointer allocations like:
//
std::shared_ptr<Type> name = std::shared_ptr<Type>(new Type(...));
name = std::shared_ptr<Type>(new Type(...));
std::shared_ptr<Type> name(new Type(...));
//
// with calls to the make_shared factory function, e.g:
//
auto name = std::make_shared<Type>(...);
name = std::make_shared<Type>(...);

As you can see, the revised syntax is at worst as concise, and in some cases much more concise, than the previous code. And, doing this may give us an infinitesimal performance/memory improvement (though I don't expect it's measurable except in contrived benchmarks).

For said contrived benchmarks, see: https://www.modernescpp.com/index.php/memory-and-performance-overhead-of-smart-pointer

[codecov]

Codecov Report

Merging #556 into develop will increase coverage by 0.56%.
The diff coverage is 53.52%.

@@             Coverage Diff             @@
##           develop     #556      +/-   ##
===========================================
+ Coverage    48.77%   49.33%   +0.56%     
===========================================
  Files          129      129              
  Lines        10036    10207     +171     
===========================================
+ Hits          4895     5036     +141     
- Misses        5141     5171      +30     

Impacted Files	Coverage Δ
include/DummyReader.h	0.00% <ø> (ø)
include/Frame.h	100.00% <ø> (ø)
include/effects/Pixelate.h	0.00% <ø> (ø)
src/ChunkWriter.cpp	0.00% <0.00%> (ø)
src/Qt/VideoRenderWidget.cpp	0.00% <ø> (ø)
src/QtHtmlReader.cpp	0.00% <0.00%> (ø)
src/QtTextReader.cpp	0.00% <0.00%> (ø)
src/TextReader.cpp	0.00% <0.00%> (ø)
src/effects/Bars.cpp	0.00% <0.00%> (ø)
src/effects/Crop.cpp	0.00% <0.00%> (ø)
... and 26 more

---

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[jonoomph]

LGTM!

[ferdnyc]

@jonoomph I decided to let Codacy shame me into fixing that initialization issue, and replace all of the redundant Frame constructors with delegating constructors.

[jonoomph]

This one is going to have some conflicts with my new clip-refactor-keyframes branch, yikes.

[jonoomph]

This might wait until after I merge clip-refactor-keyframes branch

[jonoomph]

Okay, I'm going to bite the bullet, merge this, and then merge develop back into my clip-refactor-keyframes branch and resolve all the errors.