Change tracer default output format to vtu as in visualization.
close the temp file handle returned by mkstemp

Otherwise we are leaking open file handles and run out of them at some point.
Merge pull request #204 from tjhei/fix_open_viz_files

close the temp file handle returned by mkstemp
format files with astyle
Merge pull request #205 from tjhei/apply_astyle

format files with astyle
update parameters.tex for the manual

(add one sed command to escape hyper_shell)
update manual.pdf
Merge pull request #202 from gassmoeller/tracer_default_format

Change tracer default output format to vtu as in visualization. Before nothing happened if you choose 'tracers' as postprocessor, because you first need to choose a data format.
Merge pull request #206 from tjhei/update_manual

Update manual
Clarify a statement in the manual about the adiabatic heating term.

Also bring the code comments in sync with what the code actually does.
Fix grammar.
Merge pull request #207 from bangerth/clarify-manual-2

Clarify a statement in the manual about the adiabatic heating term.
Merge pull request #208 from bangerth/fix-grammar

Fix grammar.