Printing calculated command line

When rabix command is given option --print-cli it calculates command
line and prints the result. Other change is that job or tool must be
referenced directly using JSON pointers instead of relying that these
are under specific keys. Therefore this commit fixes issues #58 and #60
Fixing tests

Function get_tool now recieves parsed cli, not args array.
Merge pull request #63 from rabix/feature/test-command

Feature/test command

When `rabix` command is given option `--print-cli` it calculates command
line and prints the result. Other change is that job or tool must be
referenced directly using JSON pointers instead of relying that these
are under specific keys. Therefore this commit fixes issues #58 and #60