Resize secondary pane after changing secondaryPaneSize

[Femax]

Hi @zesik. I make resize secondary pane after changing secondaryMinSize param.

[coveralls]

Coverage decreased (-0.8%) to 99.206% when pulling 2628f04 on Femax:master into e0e5419 on zesik:master.

[zesik]

Hi @Femax,

Thanks for catching this and contributing! I have a few questions regarding this:

1. Changing size in the render function does not reflect on internal state, nor does it trigger resize event. Could you put it somewhere so that we could keep state organized?
2. Could you add test code for this?