Improve regular expressions for common data types in test scripts
Revert column count field delimiter in "rhizome list" from ":" to "\n"
Add a few more test cases
- Put common utility functions into testdefs.sh
- Add abspath() and realpath() functions to test framework
- Test framework now executes all tests with working directory in a temporary
directory, to avoid pollution of caller's working directory
- Improve test log verbosity
- Name test log files by test script name
