conditionally define t()

if user has enabled the todo plugin, skip defining the 'one thing'
todo function t().

diff --cc plugins/available/base.plugin.bash
index 98d1fb4,137b812..e07401b
mode 100644,100755..100644
--- 1/plugins/available/base.plugin.bash
--- 2/plugins/available/base.plugin.bash
+++ b/plugins/available/base.plugin.bash