Bug fixes, normalization of options and io, documentation changes

datatools now uses a common vocabulary for options and input/output/error handling. This changed all the tools and in some cases changed the names of options. This will brake some scripts where the option names changed, were removed or behavior standardized.

The new string command conforms with the changes while retaining its "action" oriented syntax. A number of string specific commands have been removed along with the experimental vcard2json command. The documentation has been substantially re-organized.