disable shell_file adaptor loading
small test config fixes
make shells behave on I/O redirection
improve exception messages
fixes #47
add type conversion for env config options -- those are otherwise always strings (duh)
fix configure valuetype thingie to actually have a message
implicit int -> bool conversion for cfg options
Also escape dollar signs otherwise they get evaluated too early.
Merge branch 'devel' of github.com:saga-project/saga-python into devel
more stupid string escaping
Textual correction.
fix exception test
Merge branch 'devel' of github.com:saga-project/saga-python into devel
add warning about incomplete context in test config files