This implies creating a trimmed down branch that contains almost
nothing. It will then be usable by projects that do not need the
complex build system, and by the engine itself as a submodule from
the same repository.

This is the beginning of the removal of lol::String which is not really
useful once all its tiny utility functions are implemented for std::string.

This will let us detect problems with unused return values. For instance,
if you don’t remember that normalize(q) returns a pointer and expect it
to modify the object, you’ll get this warning:

warning: ignoring return value of function declared with 'nodiscard' attribute [-Wunused-result]
    quat q(1,2,3,4);  normalize(q);
                      ^~~~~~~~~ ~

- removed 0 CR characters
 - removed 7 trailing whitespaces
 - replaced 332 tabs with spaces

Add String.split(char) to split into an array, and add a simple
char const * + lol::String free operator.

The containers no longer force the user to use the ptrdiff_t type for
size information. For convenience, size() now always returns an int,
and the size_s() method offers a way to handle arrays with more than
2 billion elements. Internally, we still use ptrdiff_t, though.

Since so much code had to be changed, I took the opportunity to get
rid of capitalised accessors for classes that are lowercase.

SDL2: Mouse is back ! With correct focus support
SDL2: Added typing support with keyboard
ShaderBuilder: Refactored and simplified Shader block creation
Several warning removal
Fixed Image::Copy

and 2) fuck the Visual Studio compiler that crashes when confused.

Added utils.h : GetRandom(Array<T>) : gets a random element in a template list with weight logic.
                T FindValue(char*) : Find the value of a safe enum from the given name (when GetName is implemented)
                swap(T&, T&) is now in here too.

- removed 49 CR characters
 - removed 2 trailing whitespaces
 - replaced 1622 tabs with spaces

string concatenation unit tests.

for substrings, and the corresponding unit tests.