[TS-23] Tasksh throws errors on unescaped parentheses

_Cory Donnelly on 2015-12-23T16:23:15Z says:_

I had expected that an interactive shell for task would be more forgiving with respect to unescaped special characters, but tasksh choked on parentheses:

```
tasksh> add This is a task that includes parens (see I told you so)
[task add This is a task that includes parens (see I told you so)]
sh: -c: line 0: syntax error near unexpected token `('
sh: -c: line 0: `task add This is a task that includes parens (see I told you so)'
```