Option to merge all markdown files into 1

[vincentmorneau]

It would be helpful to be able to generate a single .md file instead of 1 per package.

Then, converting to PDF is a snap (https://atom.io/packages/markdown-pdf), and you get yourself a portable version of your doc.

[rimblas]

This should be easy to accomplish with a config option like mergeDoc and you specify a name. Or "mergeDocs": true and we generate a projectName.md

The resulting file should probably be:

config.toc.fileName + {each}obj.fileData.name + '.md'

We should be careful that config.toc.fileName <> projectName.md ;-) or add a suffix