Reverted a change breaking the reverse flag in dwr.util.addOptions

[rogwes]

Reverted a change breaking the reverse flag in dwr.util.addOptions(selectid, map, reverse) call.

In commit 101a341d70e3166d803f4efd211ca1fbaf0c52f9 a change was introduced in dwr.util.addOptions to instead of checking if arg3 is falsy (null or false or something else that can be interpreted as false) it now checks if arg3 is null. The effect of this will is that calls like addOptions(selectid, map, false) will be interpreted the same as addOptions(selectid, map, true).thus ignoring the flag value.

[mikewse]

Hey @rogwes, thanks for finding and reporting this! I'll ask you to bear with us a little while longer. We are currently working on setting up cla-bot for our repos and once that's up and running it will post to this PR and ask you to confirm. In the meantime please update this PR and focus it on the actual bugfix. You can put all the whitespace changes in a separate PR if you desire.

[rogwes]

Oh, I'm so sorry about the white space changes, that was my IDE setting that did that. I'll fix that.

[rogwes]

Whitespaces fixed, just let me know when you need my action again.