[ec_restore] Split #run into smaller methods
[ec_restore, ec_backup] Don't switch between the webui and pivotal keys

The webui_key can be used to proxy-authenticate for pivotal just like
any other user. Thus, there is no sense in switching back and
forth. Note, this doesn't make the tool any safer, it just saves us a
few lines of code.
[ec_backup] Break #run method up into smaller methods
[ec_backup] Remove @error variable

We were not consistently using this, so its value was rather dubious.
I would love for this to be a better command line tool that returned a
sensible return code, but currently the common failure mode in this
tool is to raise an error.  Thus, all this was doing was cluttering
the code a bit.
[ec_backup] Add helper functions to reduce ChefFS duplication
Auto-configure skip_acls. Accidentally dropped during refactor.
Fixup set_user_acl
[ec_restore] create for_each_user iterator
Remove build identifier from version string

Our build system adds a tag including a timestamp and git information
to development builds.  Gem::Version doesn't understand this date
format and it isn't important in the context of this tool.  This makes
testing in dev-vm easier if you happen to be using a development
build.
Add initial tests for ec_restore and ec_backup

The coverage is still very poor, but I've put a lot of the scaffoling
in place for more tests and have covered all the low hanging fruit.
Use ui.msg rather than puts
Change chef_fs helper function signatures based on CR feedback

chef_fs_copy_pattern and chef_fs_paths now take a string rather than
a Chef::FS::FilePattern.
Only check assigned_at on Chef Server versions < 12

Chef Server 12 does not returned assigned_at and does not use
precreated org.  Adding a server version check here ensures all orgs
are downloaded on a Chef 12 server.

Fixes #54
Merge branch 'ssd/2.0-final-refactor'
Bump version to 2.0.0.beta.3