Issue #2482643: Updated README and drush makefile to account for iCalcreator...

Issue #2482643: Updated README and drush makefile to account for iCalcreator non-backwards compatibility.

iCalcreator v2.22 is not backwards compatible with v2.20.0 and earlier, meaning
it doesn't work with Date iCal.

Many thanks go to d.o user bjlewis2 for pointing that out.

README.txt

@@ -16,8 +16,8 @@ Date iCal has several required dependencies, and an optional one:
 - The Feeds module is optional. It's needed only if you you wish to import iCal
   feeds from other sites.
 
-To install the iCalcreator library, download the project's official zip file:
-https://github.com/iCalcreator/iCalcreator/archive/master.zip
+To install the iCalcreator library, download the project's v2.20.2 zip file:
+https://github.com/iCalcreator/iCalcreator/archive/e3dbec2cb3bb91a8bde989e467567ae8831a4026.zip
 Extract it, and copy iCalcreator.class.php to a folder in your Drupal site
 named sites/all/libraries/iCalcreator (you'll need to create that folder).
 
@@ -242,3 +242,7 @@ date_ical exposes.
 The libraries/windowsZones.json file, which Date iCal uses to map Windows-style
 timezone names to real timezone IDs, is from Version24 of the Unicode CLDR:
 http://cldr.unicode.org/.
+
+The author of iCalcreator made backwards incompatible changes to the library
+in the v2.22 release. Thus Date iCal does not currently support any version of
+iCalcreator after v2.20.2.

date_ical.make

 core = 7.x
 api = 2
 
-libraries[iCalcreator][download][type] = "git"
-libraries[iCalcreator][download][url] = "https://github.com/iCalcreator/iCalcreator.git"
+libraries[iCalcreator][download][type] = "get"
+libraries[iCalcreator][download][url] = "https://github.com/iCalcreator/iCalcreator/archive/e3dbec2cb3bb91a8bde989e467567ae8831a4026.zip"
+libraries[iCalcreator][directory_name] = "iCalcreator"
+libraries[iCalcreator][destination] = "libraries"