scripting to automate epub generation process

[kidpixo]

I just made an epub of all the vimways 2018 project: the process is less the semi-automated, I'm on holiday with family and don't have time to polish it.

CHANGES from master :

• modified the references to external files in the .md files to be compatible with pandoc
• copied the compiled sass css from Vimways ~ 2018
• added a makefile (not fully working) to generate a single epub with pandoc

Thanks for the great project and go on for the next year, call for paper is [here] (https://reddit.com/r/vim/comments/bj8hmk/vimways_2019_call_for_paper).