Inconsistent behavior when creating DiracMixture distributions

[Jannik Steinbring]

The default constructor of DiracMixture creates a DM with no components. When, however, passing an empty matrix to the class constructor you get the error

DiracMixture([])

Error using DiracMixture/set (line 136) Samples must be a matrix.

Error in DiracMixture (line 55) obj.set(samples);

[Jannik Steinbring]

Removes default constructor of the DiracMixture distribution. Fixes bug #2.

Also removes the default constructor unit test.

→ <<cset 302f092424b8>>