Install dependencies and change to system python in .travis.yml

- Install dependencies manually that are not on pypi
- Use system python to install packages so they can be imported in
  postgres python triggers
Increment collection's minor version when a module is republished

This includes:
 - add a row in the modules table with the new minor version
 - copying the collection tree with the modified documentids
Transform cnxml to html when a module file is added
Merge branch 'cnxml-to-html-v2' of github.com:karenc/cnx-archive into karenc-cnxml-to-html-v2
various import and SQL fixes
only trigger on index file
assorted fixes: speed, correctness, ball-of-wax
test changes to match trigger work
Use generated module_ident and insert index.cnxml last in tests
Modify .travis.yml to use cnx-upgrade cnxml-to-html-v3 branch
Assert the number of modules before and after republishing a module
extra logging for now
Fixes travis config to use cnx-upgrade #master.
Merge pull request #58 from Connexions/cnxml-to-html-v3

Cnxml to html v3