`exec` with callback failed with slient param was defined
Updated JSHint bin path and keeping it happy.
Kept existing options and re-wrote the test case.
Merge remote-tracking branch 'iapain/exec-options-fix'

Conflicts:
	shell.js
Merge pull request #56 from lge88/master

test('-L', badlink) should return true
find doesn't crash with broken symlinks
Merge remote-tracking branch 'arturadib/master'