make test backward compatible to old PHP versions 

initialize log level early The default log level needs to be initialized before everthing else, otherwise an error during the option parsing (eg. when an unknown option is passed) will result in an unessecary stack trace.

honor NO_COLOR environment variable As argued for on https://no-color.org/

Fix log level setting. closes #33 

Allow dynamic log level setting This was inspired by #32 but I am not sure this actually the way to go. Thinking a bit more about the intial post, an even better way would be to add config file reading to the Options class. Maybe from a .env file?

Merge pull request #29 from dwschultz/color-stream-fix fixes colors on streams other than stdout

do not explicitly call exit(0). fixes #21 A normally exiting PHP script will exit with error code 0 by default, so we don't need to explicitly call it in run()

introduce a more compact help screen This is inspired by #9 but implements it in a more elegant way, requiring less conditionals.

Merge pull request #16 from usox/php74-compat Ensure php7.4 compatibility

Merge pull request #14 from treehousetim/patch-1 Add an accessor function to options for bin