* fixed up config.defaults definition
tools-dir and database-dir now use defaults.home value
* added tool definition file; closes#54
* added basic PoC for waybackurls scanner; updated helpers.py test
* added Endpoint/Target parsing; updated existing tests to pass
* added tests for waybackurls
* added WaybackurlsScan to FullScan
* added documenation for WaybackurlsScan
