Merge pull request #7 from gt-/master

Extend roundup.sh with init() and cleanup() functions
Print test name before starting the test
Print init and cleanup function name if it fails
Add --test parameter to only run one testcase
Add --debug|-d for debug output
Don't call cleanup twice on error
Factor out bash error trap
Remove duplicated code and fix output of init and cleanup functions
Save return code analogous to $(stdout), $(stderr)

The expectfail function will intentionally not pass the return code
of the wrapped function call. When wrapping a 'capture' call we
can work around by saving the return code analogous to the existing
$(stdout), $(stderr) mechanism.
Don't hide the 'before' line in trace

The before function is traced nowadays. Removing the first line, i.e.
the 'before' call itself, is confusing.
Fix regression: run after even after error
Call after function in any case using an EXIT trap
capture: cleanup stdout,stderr,rc files

The same tmp files are re-used for saving stdout, stderr and the
return code of the command wrapped by the capture function.

Internally, the 'tee' tool is used for dumping the output to
the tmp files. Old data in these files will survive until the
'not appending tee' will overwrite the tmp files. If the captured
command is not printing any output the old files will even
survive the capture function.

Now cleaning these files up by truncating them to a file size
of zero:
- Before running the test
- At the beginning of the capture function (Use case: several
  catpture calls during each test)
Add function to locate the absolute path of a test plan

Add a function 'roundup_pwd()' to allow from inside a test plan to
locate it's current absolute position in the file system.

Using this function one can then locate other files located relative
to the plan file, e.g.

+-----------------------------------------------
| describe "Tests using some common functions from lib"
| . $(roundup_pwd)/../lib/common.sh
| it_works()
| {
| 	use_func_from_common
| }
+------------------------------------------------