[BUG] Consecutive comment lines in loadtxt

[Bzero]

Describe the bug
loadtxt raises a ValueError if the data file contains two consecutive comment lines.

ulab version: 6.7.2-2D

To Reproduce
Create a data file with the following content:

# A multi-line
# comment
0 1
2 3

And try to load it with loadtxt:

from ulab import numpy
print(numpy.loadtxt('data.dat'))

Results in a ValueError:

Traceback (most recent call last):
  File "code.py", line 2, in <module>
ValueError: invalid syntax for number

Expected behavior
Load the data in an array:

array([[0.0, 1.0],
       [2.0, 3.0]], dtype=float32)

Additional context
If the second comment line starts with a whitespace the error does not occur:

# A multi-line
 # comment
0 1
2 3

[v923z]

Thanks for the report, I'll try to sort it out.