Remove Maintainer, as its now redundant with Authors@R entry.
Initial infrastructure for writing 'testthat' tests.  To run, load library(devtools), and then run test().  See testthat for more options on how to run tests. Tests go in inst/tests.
New tests for MNode class, including getCapabilities().
Fleshed out getCapabilities(), and added slots in MNode for node properties that are likely desirable.