Fix appveyor build

[m-mujica]

• A treeshaking test was using a symlink file (css.js) which does not work correctly when tests are running on windows. This change replaces the link with the actual file.

• Upgrade testee to latest version

• Remove wilcards from jshint script The script does not work in Windows when wildcards are used: ERROR: Can't open lib/**/*.js (seen on appveyor build) jshint recursively lints all files when a driectory is passed to the CLI so we can pass "lib/" instead of "lib/*/.js".

• Use latest 8.x version available

[coveralls]

Coverage remained the same at 93.322% when pulling 394908b729fcd0314c2d3eb27e355af0df1969e2 on symlink into d0babf4ad5be869cfe9238592bf03b119571b4ca on master.

[m-mujica]

Hmmm the bulid now gets stuck and I have no idea why. I'll take a look at this later.

https://ci.appveyor.com/project/matthewp/steal-tools-427/builds/28696315#L635

[m-mujica]

[matthewp]

👍