mention that pytz is not optional to run the automated tests (closes #249)

diff --git a/INSTALL.txt b/INSTALL.txt
index ef0ef3c1c4251b7723cfbea1983875a6212b2ddb..e65940c1e650428f64930316fd7d44087a220a84 100644 (file)
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -7,7 +7,8 @@ Prerequisites
  * Python 2.4 or later
  * CLDR 1.7
  * Optional: setuptools 0.6b1 or later
- * Optional: pytz (strongly recommended for real time-zone support)
+ * Optional: pytz (strongly recommended for real time-zone support, mandatory 
+   to run the automated test suite)
 
 
 Installation