def store(from, path = nil)
    return unless @cache_base

    path ||= from
    clear path
    copy from, (@cache_base + path)
  end
Overwrite cache contents
When called the cache destination will be cleared and the new contents coppied over
This method is perferable as LanguagePack::Cache#add can cause accidental cache bloat.

@param [String] path of contents to store. it will be stored using this a relative path from the cache_base.
@param [String] relative path to store the cache contents, if nil it will assume the from path