micro-optimization: replacing runInNewContext with runInContext which seems to be 200x faster when using a static context
honor --descriptor for --cli and --unit as well
Merge branch 'develop' of github.com:yahoo/mojito into micro-optimization-startup
Merge pull request #863 from caridy/micro-optimization-startup

micro-optimization: replacing runInNewContext with runInContext:

- runInContext seems to be 200x faster when using a static context, and this is suppose to help with apps with many files, improving the start up time during "mojito start", and apps with many tests during "mojito test" command.
some linty stuff
Merge pull request #882 from drewfish/run-descriptor

honor --descriptor for --cli and --unit as well
Removed section on single tests, added steps for contributors, changed the commands for running individual tests.
Made an edit.
Added annotations for a couple of steps regarding the use of the --path and --port options.