Enhancement - #363 export.ical

- Added feature #363 supporting iCalendar export via the 'export.ical'
  command.
- Updated documentation.
- Removed unnecessary localization of canonical command names.

src/main.h

@@ -59,7 +59,6 @@ int handleAdd (std::string &);
 int handleLog (std::string &);
 int handleAppend (std::string &);
 int handlePrepend (std::string &);
-int handleExport (std::string &);
 int handleDone (std::string &);
 int handleModify (std::string &);
 int handleProjects (std::string &);
@@ -127,6 +126,10 @@ std::string colorizeDebug (const std::string&);
 // import.cpp
 int handleImport (std::string&);
 
+// export.cpp
+int handleExportCSV (std::string &);
+int handleExportiCal (std::string &);
+
 // list template
 ///////////////////////////////////////////////////////////////////////////////
 template <class T> bool listDiff (const T& left, const T& right)