Ruby 1.9 porting of ruby-gdsii

I've done some work to get ruby-gdsii working on ruby-1.9.1 and ruby-1.9.3.  There
were a couple bugs affecting GDS output that are fixed.  For instance, library names
would come out corrupted under 1.9.

I tried to improve the testing scenario as well.  This entailed keeping rcov for ruby 1.8
usage and moving to simplecov for ruby 1.9+.  I put some of the tests into the
standard unit test form: test/test_*.rb files.  I put in some code to launch the
coverage results in a browser.

I did some testing under Macruby and found some segmentation faults, but could not
trace it to my code changes and am not sure ruby-gdsii is at fault, so a bug still exists
here.

I found the FONTS record in the GDS files to be suspect.  I have not yet addressed
this problem.

I found the ANGLE records in the GDS to look peculiar in my output, but several tools
I tried that read the GDS files did not have trouble with them.  This too, I have not
addressed yet.

With the possible exception of Macruby seg faults, the code seems to produce
working GDS files and I believe my changes only improve the situation.  The
simplecov / unit testing changes were numerous and its possible I'll need to
fix something if others find incompatibilities with their environments, but I tried
to avoid such problems.  I will be happy to address these issues.

I hope you'll adopt the changes, but in any case I would like to know what you will
do.

Oh, I'm new to git and more familiar with svn.  I apologize if I have made any procedural
errors.

Thanks,
Dave Inman