[[ NumberExpectation ]] Added new property to ExecContext, in order to specify when we want to get a number
This avoids a useless number -> ValueRef -> number conversion
Merge branch 'refactor-syntax_unicode' into refactor-syntax_unicode_number_prediction

Conflicts:
	engine/src/exec.h
Merge branch 'refactor-syntax_unicode' into refactor-syntax_unicode_number_prediction
[[ FasterNumber ]] Avoid the creation of a container in maths commands, when the destination isn't an array
Merge branch 'refactor-syntax_unicode_number_prediction' into refactor-syntax_unicode