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/.

plugins/available/todo/todo.cfg

@@ -0,0 +1,75 @@
+# === EDIT FILE LOCATIONS BELOW ===
+
+# Your todo/done/report.txt locations
+export TODO_FILE="$TODO_DIR/todo.txt"
+export DONE_FILE="$TODO_DIR/done.txt"
+export REPORT_FILE="$TODO_DIR/report.txt"
+
+# You can customize your actions directory location
+#export TODO_ACTIONS_DIR="$HOME/.todo.actions.d"
+
+# == EDIT FILE LOCATIONS ABOVE ===
+
+# === COLOR MAP ===
+
+## Text coloring and formatting is done by inserting ANSI escape codes.
+## If you have re-mapped your color codes, or use the todo.txt
+## output in another output system (like Conky), you may need to
+## over-ride by uncommenting and editing these defaults.
+## If you change any of these here, you also need to uncomment
+## the defaults in the COLORS section below. Otherwise, todo.txt
+## will still use the defaults!
+
+# export BLACK='\\033[0;30m'
+# export RED='\\033[0;31m'
+# export GREEN='\\033[0;32m'
+# export BROWN='\\033[0;33m'
+# export BLUE='\\033[0;34m'
+# export PURPLE='\\033[0;35m'
+# export CYAN='\\033[0;36m'
+# export LIGHT_GREY='\\033[0;37m'
+# export DARK_GREY='\\033[1;30m'
+# export LIGHT_RED='\\033[1;31m'
+# export LIGHT_GREEN='\\033[1;32m'
+# export YELLOW='\\033[1;33m'
+# export LIGHT_BLUE='\\033[1;34m'
+# export LIGHT_PURPLE='\\033[1;35m'
+# export LIGHT_CYAN='\\033[1;36m'
+# export WHITE='\\033[1;37m'
+# export DEFAULT='\\033[0m'
+
+# === COLORS ===
+
+## Uncomment and edit to override these defaults.
+## Reference the constants from the color map above,
+## or use $NONE to disable highlighting.
+#
+# Priorities can be any upper-case letter.
+# A,B,C are highlighted; you can add coloring for more.
+#
+# export PRI_A=$YELLOW        # color for A priority
+# export PRI_B=$GREEN         # color for B priority
+# export PRI_C=$LIGHT_BLUE    # color for C priority
+# export PRI_D=...            # define your own
+# export PRI_X=$WHITE         # color unless explicitly defined
+
+# There is highlighting for tasks that have been done,
+# but haven't been archived yet.
+#
+# export COLOR_DONE=$LIGHT_GREY
+
+# === BEHAVIOR ===
+
+## customize list output
+#
+# TODOTXT_SORT_COMMAND will filter after line numbers are
+# inserted, but before colorization, and before hiding of
+# priority, context, and project.
+#
+# export TODOTXT_SORT_COMMAND='env LC_COLLATE=C sort -f -k2'
+
+# TODOTXT_FINAL_FILTER will filter list output after colorization,
+# priority hiding, context hiding, and project hiding. That is,
+# just before the list output is displayed.
+#
+# export TODOTXT_FINAL_FILTER='cat'