Mock calls to system functions to facilitate unit testing
Remove all syscall calls from devicemapper
Remove os from devmapper
Add devmapper struct doc
devmapper: fix typo
Devmapper: remove deprecated test helpers
Devmapper: mock all calls to libdevmapper in the unit tests, and deny them by default
devmapper: skip test which are not unit tests
Devmapper: wrap calls to os/exec for easier mocking
Devmapper: test driver initialization and its interaction with libdevmapper
Forbid syscalls in tests, add 2 new unit tests
Merge pull request #62 from shykes/devmapper-unit-tests

Devmapper unit tests