added progress bar to download_resource method

from ckanapi import RemoteCKAN

from shutil import copyfile

from progressbar import ProgressBar, Bar, Percentage

from clint.textui import progress

import os

    nonstandard Python package requirements:

      - clint

      - ckanapi

      - progressbar

    parameters:

      - NFS_path: string

        resource_path = resource_path.replace("file://CROSSBOW_NFS/", self.NFS_path)

        dest_path = destination + os.path.basename(resource_path)

        print "copying %s to %s" % (resource_path, dest_path)

        copyfile(resource_path, dest_path)

        #custom function to copy with progress bar

        def copy_with_progress(src, dst, callback, length=16*1024):

            copied = 0

            size = os.path.getsize(src)

            with open(src, 'rb') as fsrc:

                with open(dst, 'wb') as fdst:

                    while True:

                        buf = fsrc.read(length)

                        if not buf:

                            break

                        fdst.write(buf)

                        copied += len(buf)

                        callback(copied,size)

        prog = ProgressBar(widgets=[Percentage(), Bar()], maxval=100).start()

        copy_with_progress(resource_path, dest_path, lambda pos, total: prog.update(100*pos/float(total)))

        print ''

    def delete_resource(self,package,resource,delete_from_nfs=False):

        '''