Added simple support for Cargo -

the Rust build system

plugins/cargo/cargo.plugin.zsh

+function _cargo_commands() {
+    local ret=1 state
+    _arguments ':subcommand:->subcommand' && ret=0
+
+    case $state in
+      subcommand)
+        subcommands=(
+          "build:Build the current project"
+          "clean:Clean up after a build"
+          "help:Help about available commands"
+          "new:Create a new project"
+          "test:Run the tests"
+          "update:Updates list of known packages"
+          "run:Builds and runs the currecnt project"
+        )
+        _describe -t subcommands 'cargo subcommands' subcommands && ret=0
+    esac
+
+    return ret
+}
+
+compdef _cargo_commands cargo