Wrapped i2c and serial modules generically

Created wrapper definition in 'my' module and applied it for
node-serialport and node-i2c modules. Hopefully this simplifies
adding future external modules, including node-i2c.
my.wrapOpen: replaced fixed open with function and variable parameters

To enable a more flexible "open" definition needed by the i2c library,
the my.wrapOpen function now takes an array of arguments for the created
open function and is provided with a definable call to perform the open
task with the module, rather than simply being provided a method defined
by the module.
test-i2c.js: Created initial test case
test-i2c: added exit when running remote
README.md: add serial and i2c functions