bump version to 0.2.4

ChangeLog

@@ -1,3 +1,20 @@
+0.2.4	fixed compiler macro misplacement (github#4).
+
+	fixed invalid free (github#5).
+
+	fixed invalid memset(0) in ps_close().
+
+	added python binding, not enabled by default,
+	use --with-python-binding to turn it on.
+
+	certain generated files are no more generated by
+	autogen.sh, but manually by myself and put into
+	git, because the generation isn't portable. also
+	fixes github#3.
+
+	disabled conftests when cross compiling.
+
+
 0.2.3   Z85 block encoding changed. 4 bytes are appended
 	to each input block to denote if and how many
 	zeroes have been used for padding, necessary