updates to description of topotools and fgmax
changes to geoclaw docs for 5.2.0
update 5.2.0 changes and reorganize contents to move changes up
add 5.2.0 release date
update to 5.2.0 in installing.rst
Merge pull request #61 from rjleveque/new_for_5.2.0

New for 5.2.0