Handle the case of empty runfiles strings.

Fixes from pull request comments

This commit addresses issues found during the code review:
- gmakefile had the wrong dependency of library on objects
- gmakefile: $(generatedtestargs) now depends o

Fixes from pull request comments

This commit addresses issues found during the code review:
- gmakefile had the wrong dependency of library on objects
- gmakefile: $(generatedtestargs) now depends on $(generatedtest)
instead of invoking gmakegentest.py as well
- TESTTARGETS should be calculated as needed ("=" instead of ":=")
- Determining requirements based on arguments is fraught with peril, but
is now more robust
- Added support for finding the yaml input file so that it is
automatically added to localrunfiles. This allows for more robust testing.
- Bug fix for localrunfiles: Shell script test harness now copies
runfiles to local directories.

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Bugs and features per discussion on bitbucket

1 convertExamples now handles multiple filters correctly
2 There was a bug in writing out the TODO block that was caught in
implementing filter
3 Ver

Bugs and features per discussion on bitbucket

1 convertExamples now handles multiple filters correctly
2 There was a bug in writing out the TODO block that was caught in
implementing filter
3 Verbosity level changed to be more silent by default, but to enable
V=1 to make more verbose
4 Skip changed from 'not ok' to 'ok'
5 localrunfiles feature implemented:
This copies over input file if the description language contains localrunfiles.
6 filter_output implemented:
This has a new diff line that allows filtering of the output before
diffing.
7 Preliminary logging enabled. This uses a simple tee similar to the
build. The logging is done in the tests directory however.

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Introduce new test harness and script to convert from the old makefile approach to the new test harness