[WIP] Update WAVM to 7th Feb 2019

[axic]

[axic]

@chfast apparently instead of this mess we do in the install scripts, the WAVM author suggests the following: https://github.com/WAVM/WAVM/issues/128

I'm not versed in cmake at all to know if that helps. Can you check?

[codecov-io]

Codecov Report

Merging #493 into master will increase coverage by 0.98%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #493      +/-   ##
==========================================
+ Coverage   51.18%   52.17%   +0.98%     
==========================================
  Files           8        8              
  Lines        1346     1311      -35     
  Branches      130      129       -1     
==========================================
- Hits          689      684       -5     
+ Misses        630      600      -30     
  Partials       27       27

[chfast]

Can you check?

This will not work in our case unless you add it to Hunter.

[axic]

@chfast can you review this? My only requirement for this PR would be that we do not have larger memory leak due to our code than before.

[axic]

This is broken after the rebase 😢