Speed up new shell startup

[danmactough]

Only run chpwd when the shell loads if there is a .node-version file in the current directory.

This speeds up opening a new terminal when the working directory doesn't have a .node-version file.

The hook still runs when you change directories.

[coveralls]

Coverage remained the same at 100.0% when pulling 2871c64 on danmactough:master into 24e1b1d on wbyoung:master.

[ljharb]

Does avn not look for .node-version files in parent directories as well, like .nvmrc?

[danmactough]

Does avn not look for .node-version files in parent directories as well, like .nvmrc?

Ah. Indeed it does. Never relied on that feature. 😜

[wbyoung]

Thanks for the thought, though, @danmactough.

[danmactough]

Haha no problem @wbyoung thanks for this awesome tool that makes my life better 👏