Added Todo syntax highlighter

resources/todo.sublime-syntax

@@ -0,0 +1,77 @@
+%YAML 1.2
+---
+name: todo.txt
+scope: text.todo
+variables:
+  date: '(\d{4}-\d{2}-\d{2}(?:\s+|$))'
+  prio: '(\([A-Z]\)(?:\s+|$))'
+contexts:
+  main:
+    - match: '^\s*x\s'
+      push: done
+
+    - match: ""
+      push: todo
+
+  done:
+    - meta_scope: comment.line
+    - include: check_prio
+
+  todo:
+    - meta_scope: text.todo
+    - include: check_prio
+
+  desc_fallback:
+    - match: '\s'
+    - match: ""
+      push: desc_start
+
+  check_prio:
+    - match: "{{date}}"
+      scope: constant.numeric
+      push: check_date2
+
+    - match: "{{prio}}"
+      scope: keyword
+      push: check_date
+
+    - include: desc_fallback
+
+  check_date:
+    - match: "{{date}}"
+      scope: constant.numeric
+      set: check_date2
+    - include: desc_fallback
+
+  check_date2:
+    - match: "{{date}}"
+      scope: constant.numeric
+      set: desc_start
+    - include: desc_fallback
+
+  # Any preceeding whitespace has been read
+  # safe to assume start of match is succeeds whitespace
+  desc_start:
+    - match: '@\S+'
+      scope: string
+      push: desc
+    - match: '\+\S+'
+      scope: variable.function
+      push: desc
+    - match: '\b([^\s:]+):([^\s:]+)\b'
+      captures:
+        1: entity.name
+        2: entity.name.tag
+      push: desc
+    - match: ""
+      set: desc
+
+  desc:
+    - match: '(?:\s|^)@\S+'
+      scope: string
+    - match: '(?:\s|^)\+\S+'
+      scope: variable.function
+    - match: '\b([^\s:]+):([^\s:]+)\b'
+      captures:
+        1: entity.name
+        2: entity.name.tag