Add help button to the comparison mode

[GoogleCodeExporter]

More info needs to be provided in comparison mode.

It can be done by a help button, which is for the following issues::

1. Hints for building chains: e.g. Add None will remove an algorithm component.
2. Provide user with guidance for using a feature selector, 
   number of features generated by various extractors. Or other hints on choosing a good chain.
3. Other possible issues such as "stop" does not stop immediately.

In addition,  in comparison mode, buttons are taking up too much horizontal 
space, making chain window hard to read.  So we need to put the buttons in 2 
columns instead of 3 or more.

Original issue reported on code.google.com by jzho...@gmail.com on 4 Oct 2013 at 6:49

[GoogleCodeExporter]

For UI consistency, it would be better to call the button "hints"/"tips" since 
Help menu is already at the menu bar.

Original comment by jzho...@gmail.com on 7 Oct 2013 at 8:38

[GoogleCodeExporter]

Original comment by jzho...@gmail.com on 21 Oct 2013 at 6:57

• Changed state: Started

[GoogleCodeExporter]

Fixed in release 1.2.9

Original comment by jzho...@gmail.com on 4 Nov 2013 at 9:45

• Changed state: Fixed