Merge pull request #25 from mandli/master

Update to new Riemann interface
Add install option 'symlink-only'.
Merge pull request #27 from ketch/no_pyclaw_install

Add install option 'symlink-only'.
Merge pull request #28 from mandli/master

Update to all repositories for RC for 5.0
Add pointers to change files in subpackages
Increment release candidate version
Merge remote-tracking branch 'clawpack/master'
bumped version to 5.0.0rc-gamma
updated to 5.0.0rc-gamma, new release candidate
Merge pull request #31 from rjleveque/5.0.0rc-gamma

5.0.0rc-gamma
5.0.0 final version (?)
Merge pull request #32 from rjleveque/5.0.0-final

5.0.0 final version (?)
Update to release candidate alpha for 5.1
Update version
Merge pull request #34 from clawpack/5.1-rc-alpha

Update to release candidate alpha for 5.1
Redirect stdout to a file install.log during install to avoid all that
output to the screen.  Fixes
https://github.com/clawpack/pyclaw/issues/338.
Ensure that stdout is restored if something goes wrong during install.
Merge pull request #35 from ketch/redirect_stdout

Redirect stdout to a file install.log during install to avoid all that output to the screen
Update for 5.1.0 release
Merge pull request #36 from rjleveque/5.1.0-final

Update for 5.1.0 release