Pass log file as command line option

[alek]

By default, grunf should run to stdout and only write to log file if appropriate cmd option passed

Example:

lein trampoline run -c conf.example.clj <- logs to stdout
lein trampoline run -c conf.example.clj -log logs/foo.log <- logs to foo.log file

[dryman]

The current CLI options

Usage:

 Switches               Default  Desc                                                 
 --------               -------  ----                                                 
 -c, --config                    Path to the config file                              
 -h, --no-help, --help  false    Print this message                                   
 --log                           log path for log4j. If not specified, log to console 
 --log-level            debug    log level for log4j, (fatal|error|warn|info|debug)