Change default output path from ./ to emperor

The -o option now has a default, previously it was not the case as it
would manually prepend ./ to every output.

Fixes #60
Added Jenkins build status icon to README.md
Merge pull request #70 from jrrideout/readme_ci_link

Added Jenkins build status icon to README.md
Use aboslute paths in all_tests.py

The scripts directory was not being processed as an aboslute path, this
was in turn causing failures when the module was installed and the
--emperor_scripts_dir option was passed.

Fixes #69.
Merge pull request #71 from ElDeveloper/issue_69

Use aboslute paths in all_tests.py
Merge pull request #62 from ElDeveloper/issue_60

Change default output path from ./ to emperor