Merge pull request #15 from amorphic/master

Ports are not always floats so returning as strings instead
add quiet output option

  - -q: outputs just a number, without unit. usefull for parsing in external
    programs
  - add -c and -f options for choosing unit (degress celcius of
    farhenheit)
Merge pull request #18 from saimonn/master

add quiet output option
Patch looks reasonable.