Merge pull request #5 from johnlaing/master

add convenience functions for set operations
bump version for dev version
pull request #5 by John adding three set operations
new minor version
making R CMD check happy by switching to vectors
drop comments accidentally committed
add tests for execv, set helpers
Merge pull request #7 from johnlaing/bugfix/vararray

Bugfix/vararray
Merge pull request #6 from eddelbuettel/bugfix/vararray

Bugfix/vararray
updated ChangeLog
release 0.1.2