Create a wrapper to also allow ''scantable'' creation directly from a file on the web.

{{{
import urllib2
import tempfile
from asap import scantable

def urlscantable(*args, **kwargs):
    if isinstance(args[0], basestring) and args[0].startswith("http"):
        url = urllib2.urlopen(args[0])
        tfile = tempfile.NamedTemporaryFile()
        tfile.write(url.read())
        return scantable(tfile.name, *args[1:], **kwargs)
    else:
        return scantable(*args, **kwargs)

if __name__ == "__main__":
    s = urlscantable("http://www.narrabri.atnf.csiro.au/mopra/DataDepot/2008-03-12_0932-M999.rpf")
    print s

}}}