Change version to 2.1.0, i.e., use common semantic versioning system including…

Change version to 2.1.0, i.e., use common semantic versioning system including patch number for bug fix releases.

CMakeLists.txt

@@ -8,7 +8,7 @@ include (utils)
 # ----------------------------------------------------------------------------
 # package information
 set (PACKAGE_NAME      "gflags")
-set (PACKAGE_VERSION   "2.1")
+set (PACKAGE_VERSION   "2.1.0")
 set (PACKAGE_STRING    "${PACKAGE_NAME} ${PACKAGE_VERSION}")
 set (PACKAGE_TARNAME   "${PACKAGE_NAME}-${PACKAGE_VERSION}")
 set (PACKAGE_BUGREPORT "https://code.google.com/p/gflags/issues/")