add .prm.out files to make eclipse happy

Even though the .out files get generated by the Makefile in doc/ when
you build manual.pdf, it turns out eclipse is complaining when the .out
files are not present.
Also remove the .out from .gitignore again and do not generate a .out
for doc/manual/empty.prm because it is not used.
Add remove 'all' as a possibility for model names and other plugins.
Merge pull request #102 from bangerth/fix-defaults

Add remove 'all' as a possibility for model names and other plugins.
multiplex output

All output is now also put into output/log.txt in addition to the
screen.

Some error messages are now only printed on processor 0 instead of on
every processor.

The header should be printed in case of early failure (for example no
prm given), but also piped into the output file. For that reason it now
lives in global.h. Update the version script to find the version info.
update changes.h
Merge pull request #103 from tjhei/multiplex_output

multiplex output
Do not create output from processes != 0 if there is an error in the input file.
Write a changelog entry.
Merge branch 'fix-massively-parallel-error-message' of https://github.com/bangerth/aspect

this closes pull request #104.
Add first couple of files for the Davies benchmarks.
Minor modifications of the input file.
Update.
Update for another postprocessor.
Update the list of postprocessors.