Code and Text blocks may not always be alternate

[ioggstream]

I expect

Code and Text block to be subsequent

Instead

The implementation forces code and text blocks to be alternate

[goerz]

I would propose just using a double blank line to separate consecutive markdown cells. In the notebook to markdown conversion, simply add a blank line before and after every text block. In the markdown to notebook conversion, start a new cell anytime there is more than one blank line.