Basic named commands now print usage if the argument parser fails on empty input.  Fixes #776.
Basic named commands now print usage if the argument parser fails on empty input.  Fixes #776.

The Help for these commands now needs to be cleaned up, since they were not written with
this feature in mind.  In particular,

* consider adding syntax summaries in the short help strings
* alternatively, add the syntax summary data elsewhere for use specifically by this feature
* display a better message when there is no short help string, such as
   "See 'help <command>' for usage." or just displaying the lower level error message, such as
   "Expected whitespace"

jkinkead/sbt,xuwei-k/xsbt,xeno-by/old-scalameta-sbt,sbt/sbt,dansanduleac/sbt,twitter-forks/sbt,jasonchaffee/sbt,xeno-by/old-scalameta-sbt,jkinkead/sbt,mdedetrich/sbt,dyx/sbt,jaceklaskowski/sbt,sbt/sbt,xeno-by/old-scalameta-sbt,pocketberserker/sbt,jkinkead/sbt,Duhemm/sbt,mdedetrich/sbt,xuwei-k/xsbt,sbt/sbt,sbt/sbt,xeno-by/old-scalameta-sbt,dyx/sbt,twitter-forks/sbt,xuwei-k/xsbt,twitter-forks/sbt,xuwei-k/xsbt,sbt/sbt,mdedetrich/sbt,jaceklaskowski/sbt,corespring/sbt,jkinkead/sbt,twitter-forks/sbt,twitter-forks/sbt,dyx/sbt,Duhemm/sbt,jaceklaskowski/sbt,jaceklaskowski/sbt,xuwei-k/xsbt,dyx/sbt,Sciss/sbt,pdalpra/sbt,jaceklaskowski/sbt,mdedetrich/sbt,Duhemm/compiler-bridge,adriaanm/sbt,xeno-by/old-scalameta-sbt,jkinkead/sbt,dyx/sbt,sbt/sbt,sbt/sbt,xeno-by/old-scalameta-sbt,mdedetrich/sbt,mdedetrich/sbt,som-snytt/xsbt,mdedetrich/sbt