add todo.txt-cli as a plugin
Since it is referenced in the default .bash_profile and in aliases and
themes, why not make it an official plugin?
This creates a 'todo/' directory in /plugins/available, and installs
todo.sh and friends there. Tab completion and the 't' alias should work
out of the box.
Note: it was also necessary to modify .gitignore to ignore the files
todo.sh generates in custom/.
diff --git a/.gitignore b/.gitignore
index 25042cb..b27cddd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,6 @@
*/enabled/*
.DS_Store
-custom/*.bash
+custom/*
!custom/example.bash
.rvmrc
aliases/custom.aliases.bash