Added simple benchmark for comparions of different ways of matrix setup for a purpose of matrix tutorial - CMakeLists.txt.

Added simple benchmark for comparions of different ways of matrix setup for a purpose of matrix tutorial.

Added DenseMatrixRowView::setElement with localIdx parameter for compatibility with sparse matrices.

Refactoring: small fixes and improvements

Closes #71

See merge request !79

Also removed unnecessary getVectorLength function from getEntityMesure.h

Fixes #71

- the sum function was unused
- inline is useless for template functions

CUDA 11.2

See merge request !78

The condition is always satisfied, since getAllocatedElementsCount
returns the size of the values vector view, which was bound just prior
the assert.