Fixing iss38 (conditionalPanel within bsCollapsePanel).

[mattflor]

Hopefully, this fixes issue #38. I am not sure though whether this is just tinkering with the symptoms.
If conditionalPanels are nested within bsCollapsePanels then somehow the sbs-value data array of the parent bsCollapse may contain multiple entries for the same bsCollapsePanel.
Basically, all this fix does is the following:

• on bsCollapsePanel hide events: remove ALL entries of the bsCollapsePanel to hide from the bsCollapse's sbs-value array, using the new function removeA()
• on bsCollapsePanel show events: only push the bsCollapsePanel to the sbs-value array if it is not in there already

What I was not able to find out is why multiple entries show up at all.