Fixes typo in an error message

[skip ci]
Makes 'reprounzip info' show inputs and outputs
load_config() adds '{in,out}put_files' keys

This allows backwards-compatibility.
Factors get_ssh_parameters()
Implements 'vagrant upload' to replace input files
Implements 'vagrant download' to get output files
Removes obsolete "run vagrant up" message
Copies file with sudo + restore owner/perms
Merge branch 'vagrant-transfers' into 'master'
Fixes the packer failing on temporary directories

In addition to the configuration file, the packer also reads the trace
to pack directories in which files were created or that were used as
working directory of processes. However these might have been temporary
directories that no longer exist; in this case, an OSError really
shouldn't be allowed to propagate.
Bumps reprozip version to 0.3.1
Makes sure pip calls setup.py scripts correctly
Minor fixes to Vagrant
Factors make_unique_name()
Adds plugins to check_style test
Reworks tests

Adds support for unit tests!

The 'tests' package now takes arguments --unittests and --functests.
Travis scripts were updated to no longer use run.py.
Adds tests for unique names generation
Adds doc for escape()

[skip ci]
Adds irange() util
Adds dict utils (iteritems(), itervalues(), ...)