Add 'var' parameter for passing variable references

  - This eliminates the need for calling get_option_<type> in simple cases.
Minor updates
v0.8.2: Bugfix for file input

  - When reading options from a file, the last option in a file would
    not be read unless there was a newline (or possibly a blank) at
    the end of the file. Fixed.

  - Added a few comments too