Detect and raise IOError exception for LiDAR files (fixes #472)

[kinverarity1]

Example:

>>> import lasio
>>> lasio.read(r"C:\Users\kinverarity\Downloads\MineralsOF_las (2)\MineralsOF_las\244000_6595000.las")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\devapps\kinverarity\projects\lasio\lasio\__init__.py", line 34, in read
    return LASFile(file_ref, **kwargs)
  File "C:\devapps\kinverarity\projects\lasio\lasio\las.py", line 80, in __init__
    self.read(file_ref, **read_kwargs)
  File "C:\devapps\kinverarity\projects\lasio\lasio\las.py", line 174, in read
    raise IOError("This is a LASer file (i.e. LiDAR data), not a Log ASCII Standard file")
OSError: This is a LASer file (i.e. LiDAR data), not a Log ASCII Standard file