Task arguments can't contain =

[welearnednothing]

From comment in #310.

Task arguments can't contain an equal symbol.
Currently, the = symbol is used to determine that an environment variable is being passed, and this applies to task arguments as well.

Jakefile:

task('test', function(x) {
  console.log(x);
});

jake test[abc def=123] yields:

abc

jake test["abc def=123"] yields:

jake aborted.
Error: Unknown task "default"
at TaskBase.nextPrereq (/Users/jcarnes/Work/jake/lib/task/task.js:196:15)
at TaskBase.runPrereqs (/Users/jcarnes/Work/jake/lib/task/task.js:170:14)
(See full trace by running task with --trace)