Add node-info function

Minimal configuration required prior to calling node-info is:
ztyle -s ':prezto:module:node:info:version' format '%v'

$node_info[version] will contain the current version of node.js
on the path, if nvm is loaded.

This information can be used in prompts like $ruby_info.

modules/node/functions/node-info

@@ -0,0 +1,26 @@
+# vim: ft=zsh
+#
+# Exposes information about the node.js environment via the $node_info
+# associative array.
+#
+# Authors:
+#   Zeh Rizzatti <zehrizzatti@gmail.com>
+#
+
+local version
+local version_format
+local version_formatted
+
+unset node_info
+typeset -gA node_info
+
+if (( $+functions[nvm_version] )); then
+  version="${$(nvm_version)#v}"
+fi
+
+if [[ -n "$version" ]]; then
+  zstyle -s ':prezto:module:node:info:version' format 'version_format'
+  zformat -f version_formatted "$version_format" "v:$version"
+  node_info[version]="$version_formatted"
+fi
+