ZF-3674: Add default locale to Zend_Measure

Description

Add a default locale to Zend_Measure to allow setting one locale for all instances which is used when no locale is set. Something like static setLocale.

Comments

A default locale has been added within trunk. Use setDefault() / getDefault() and 'default' as autosetting.

Beware: As mentioned this is a BC break. Be aware of possible merging problems when using the old auto behaviour.

Updating for the 1.6.0 release.