[CDF-430] i18n improvements
	- cdf-pentaho-base CdfHtmlRenderer now calls cpf-core's MessageBundleHelper
	- removed cdf-pentaho-base's MessageBundleHelper
	- updated template-dashboard-*.html i18n block
	- added ICdfEnvironment.getSystemDir(), same as you would find in ICdeEnvironment
	- fixed a bug found in CdfApiPathProvider.getPluginStaticBaseUrl()
	- cdf-core's ivy.xml did not have a junit dependency declaration, rendering impossible to do ant test in local machines ( CI jobs work )
	- updated 4.x / 5.x i18n documentation ( Documentation > Advanced > Internationalizing CDF )
	- updated 4.x / 5.x i18n samples ( Samples > Internationalized Chart Sample )
Merge pull request #325 from pedrofvteixeira/CDF-430

[CDF-430] i18n improvements