Fix seg-fault where synthetic topo was used

Since it is not clear how to deal with synthetic topography with dtopo files
it is left up to the specification of the topography to determine the changing
topography if applicable.  This patch corrects for the fact that certain
parameters were not being set (which caused a seg-fault) and also removes
a deallocation problem.
fixed input_units in read function
added scratch directory for downloaded or generated data files
Updated chile2010 example to use new dtopotools and to download and generate files in scratch directory
Merge remote-tracking branch 'rjleveque/dtopotools2' into dtopotools2

* rjleveque/dtopotools2:
  Tests all work, new IO test for dtopo added
  Raise nose.SkipTest if scipy not installed
  Add documenation and fix bugs
  Add old dtopotools class structure for reference
  Merge newest changes with various bug-fixes
modify verbose message
change SCRATCH to scratch
added most2geoclaw.get_comMIT_topo function to grab topo file from web, but doesn't always work!  This module needs refactoring.
Fixed default rigidity mu=4e10 not 4e11 since standard units are now Pa
Topography.read doesn't handle http addresses
set _X and _Y to None in Topography.read so if a new file is read it, X and Y will be regenerated when required.
Fixed maketopo.py file in chile2010 example for latest tools and to also plot if requested.
Fixed exected Mw values in unit test assertions - changed because of change to default mu value in 947d7d9
Fixed up doc strings in modules so that automodule can be used in clawpack/doc/doc to create documentation pages
changed kmltools.quad2kml ordering of xy points and added verbose option, docstrings
Removed SCRATCH in order to rename to scratch
recreated scratch directory
Changed dz_list attribute of DTopography to DZ  as ndarray of rank 3.  Change DZ to dZ?
tests/bowl_slosh example seemed to run fine in travis but gave an error on my machine. The first two lines of regression_data.txt are only difference.  Note that gauge location is right on edge between wet cell and dry cell at t=0, should probably move it
moved gauge in tests/bowl_slosh and updated regression_data.txt