show meaningful less errors

show this...

````
error: Less compilation error
FileError: '../flatstrap/less/bootstrap.less' wasn't found.

1 @import "../flatstrap/less/bootstrap.less";
2 @import "../flatstrap/less/responsive.less";
````
instead of this...

````
verbose: Server stopped.

/example/node_modules/sails/node_modules/less/lib/less/parser.js:390
                        else                                  throw new(LessEr
                                                                    ^
[object Object]
````