Instead of relying in npm global installation hook for auto reshimming,
a pretty obscure functionality of npm, I just wrote a wrapper script
that intercept calls for npm and invokes asdf reshim whenever necessary.
The wrapper needs to be configured manually by the user, following the
practices of other plugins with similar settings.
I also wrote an utility for printing the current wrapper path easing the
configuration of new environments.
README now has an example of how to configure auto-reshimming.
There's also a notice on plugin installation about setting up the
auto-reshimming configuration.
A notice was also added to the install command, so that we reach more
people about the changes.
Per issue #46 the `ASDF_INSTALL_VERSION` variable is not available in global NPM installs. Instead the `npm_config_node_version` is provided by NPM during this situation.
This change offers a fallback in these cases. Since a version will be available this will significantly speed up the postinstall during global NPM installs.
Fixes#46
