File Import

- Implemented import from task 1.4.3, 1.5.0, 1.6.0, plain text,
  todo.sh and task command line files.
- Implemented unit tests to cover the above.

src/parse.cpp

@@ -235,7 +235,7 @@ bool validDate (std::string& date, Config& conf)
 {
   Date test (date, conf.get ("dateformat", "m/d/Y"));
 
-  char epoch[12];
+  char epoch[16];
   sprintf (epoch, "%d", (int) test.toEpoch ());
   date = epoch;