Fix board resize

[marknn3]

Board resizing had several issues and was very complex. This PR fixes all known issues and implements the following:

• Simplify and unify board resizing
• Resize undo/redo/replay buffers
• Resize solution
• Protect board content in Solution mode

Fixed issues:

• Answer check does not work after resize.
• Undo/redo buffer destroyed.
• Board scrambled/corrupted when (accidentally!) sized too small.
• FreelineE does not always resize properly (when line is on center, type=0)
• cages, arrows and thermos with custom color can crash resize (when e.g. pq_q_col.killercages contains null).

This PR fixes #143

[swaroopg92]

Thank you. I have merged it. There were a couple of changes I made. I fixed an undo greying bug (not because of this PR but it was already there in master branch). The "row" and "column" wordings were swapped and was updated.