Inconsistent result into `leaf.x` containing `list` of `None` and `ERROR`

[yasirroni]

With the same problem that is actually feasible, MIOSQP give inconsistent result, where sometimes it is feasible and give a good result and sometimes stuck into leaf.x containing list of None that make numpy round error.

See:

miosqp/miosqp/workspace.py

Line 254 in ac67233

int_feas_false = abs(x_int - np.round(x_int)) >\

Can you fix this guys?

[yasirroni]

Please review #16