add a get_destdir.
unimplemented is fatal. exit at the end.
basic lib install.
misc removal.
don't pass the cmd args to the cmd callback.
add a stub get subcommand.
fix bug where subcommands did not receive args through Arg.parse_argv
small style change
allow to specify targets in build.

* syntax is slightly odds as to make sure stuff are uniques
* propably can search the target before and automatically try to resolve
  from inexact name.
* need better errors in case target doesn't exists.

fix #35.
Fixed the annot patch