minimal R package framework for new 'QuantLib' R package generated by SWIG
old examples/ is now demo/

demo/ is a standard (though optional) R package directory
also added 00Index file
new file .Rinstignore

Files listed in this file will not be installed by into the package install location
minimal update to README.txt
Add missing files to 'make dist' target.
Update .gitignore after generated files were moved.
Fix compilation and installation rules.

They now call the appropriate (I hope) R commands.
Merge pull request #19.

The R extension is now built as a standard R package.