cat elpa/install.log when travis build failed
Update tools/el4t
Merge branch 'travis-build-fix'

As rejeep/carton#15, carton uses Emacs to find CARTON_DIR.
This was problematic for el4t because it runs git in the
proxy script.  This was fixed by:
tkf/el4t@d868c342b85030b1dd62be2f2fcff669c254bb9b
Use site.addsitedir when adding virtualenv

`sys.path.insert(0, path)` is used to override default packages.
`site.addsitedir` is used to additionally treat `*.pth` files.
Although paths specified by `*.pth` files are appended to `sys.path`
instead of being prepended, it is still better than not adding
these paths.

fixes #30