Improve readability of results

[fain182]

This PR should fix the #36 and improve readability with other subtle improvements:

• show time in seconds instead of milliseconds
• colorize class name to make it more readable
• avoid dots at the start of the line to avoid confusion with the test results' report

[localheinz]

@fain182

What do you think about additionally rendering an empty line after the header and before the footer?

[fain182]

What do you think about additionally rendering an empty line after the header and before the footer?

I think it's a good idea..

@johnkary what do you think about merging this?

[johnkary]

@fain182 Please see my comment pending review here about conditional color output: https://github.com/johnkary/phpunit-speedtrap/pull/47/files/#r202464176

• show time in seconds instead of milliseconds

I am concerned this change would cause differences between the slow time display and the slowness threshold configuration. Display would be in seconds while slowness threshold in milliseconds. I do not think changing the configuration to seconds would make this library easier to use. What do you think about these concerns?

• avoid dots at the start of the line to avoid confusion with the test results' report

I support this change. Could we also replace the trailing dots in the header with a colon:

You should really fix these slow tests (>500ms)...
   change to
You should really fix these slow tests (>500ms):