luci-app-ddns: modified to support ddns-scripts 2.1.0-2

- moved /usr/lib/ddns/dynamic_dns_lucihelper.sh to ddns-scripts package
- fixed error message when validating proxy
- modified validating ip_script to allow the usage of parameters
- using ipkg/postinst AND ipkg/postinst-pkg as long as LuCI Makefiles did not
	fullfil requirements of new OpenWrt default_postinst and default_postrm
	reported in Issue #255
- cleanup whitespaces at line ends

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>
Merge pull request #256 from chris5560/master

luci-app-ddns: modified to support ddns-scripts 2.1.0-2
luci-app-ddns: Update to support ddns-scripts 2.1.0-3

- modified controller
-- remove support for ddns-scripts Version 1.x
-- ddns-scripts not correctly installed do not start
-- no config file create an empty one
- moved log settings to advanced tab
- set default syslog level "Notice"
- removed special handling for dynamic_dns_helper.sh in postinst

Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>
Merge pull request #262 from chris5560/master

luci-app-ddns: Update to support ddns-scripts 2.1.0-3
Merge branch 'master' of github.com:openwrt/luci