path + sh updates

* path updates
    * pep8 formatting
    * adds methods to the path class for convenience
        * cp: reads the src, and determines whether to copy a dir or file
        * sym: will first unlink if dest already exists
    * changes path operations to return self for chainability
* sh updates
    * nests an output of info to be able to better tune output by default
    * adds sh2 method: which attempts to be a more terse method for invoke comamnds
Merge pull request #2 from gregorynicholas/path-updates

path + sh updates