feat(cmd): add flag to suppress header/footer

[raghur]

see #83 is this what this issue refers to?

[codecov]

Codecov Report

Merging #95 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #95      +/-   ##
==========================================
+ Coverage   81.71%   81.73%   +0.01%     
==========================================
  Files          35       35              
  Lines        2100     2102       +2     
==========================================
+ Hits         1716     1718       +2     
  Misses        258      258              
  Partials      126      126

[xcoulon]

thanks for this PR, @raghur!

[xcoulon]

@raghur looking at asciidoc and asciidoctor, I think that we should align with them in term of commands, so the switch from one tool to another would be more straightforward. I've opened a new issue about it, in order to take the source file to convert without the need for a specific flag, and replace the -n with -s. Feel free to take a look at it if you want ;) (since you've already worked on the cmd pkg)