recursive configuration logic

semver will now recursively look in parent folders to find a .verison file
like in git.  The condition to stop looking is when it encounters a
non-writabe folder.
removed previous required parameters to get-version
fixed tests failed silently
implemented --pretend option

Pretending a bump will only output the new version without updating the
version file.
bumped version 0.4.0
Merge branch 'release/0.4.0'

* release/0.4.0:
  bumped version 0.4.0
  implemented --pretend option
  fixed tests failed silently
  removed previous required parameters to get-version
  recursive configuration logic