1. DOM handling of big XML files. 2. DCG for dates.

* [COWSPEAK,EXT] cowsay/2 now has more useful arguments, in line with cowspeak/2.
* [DCG_DATE,NEW] New module with DCG rules for parsing/generating days, months, and dates. (Years are treated in module DCG_YEAR.)
* [IO_EXT,NEW] Added copy_stream_line/2 for copying a single line from one stream to the other.
* [XML_STREAM,NEW] New module allowing the DOM of a hige XML file to be processed without requiring tons of RAM.
Several extensions and additions while converting the energylabels data from XML to RDF.

* [COWSPEAK,EXT] cowsay/1 and cowspeak/1 now accept terms (used to be atoms only).
* [DCG_DATE,EXT] No longer use DCG_YEAR, DCG_CARDINAL. The dates we want to parse come with many rediculous assumptions...
* [FILE_EXT,NEW] Added safe_move_file/2.
* [IO_EXT,FIX] Typo in copy_stream_line/2.
* [META_EXT,EXT] run_on_sublists/2 now collects all threads that were started and lets the cow communicate threads that did not end properly.
* [THREAD_EXT,SC] Simplefied the way in which thread_start/4 calls the threaded goal.
* [THREAD_EXT,DOC] Added documentation for thread_success/1.
* [XML_STREAM,EXT] Problems with streaming to/from tmp files. We now use a single, normal file called the CopyBuffer for this.
* [XML_TO_RDF,NEW] New module for generic DOM2RDF transformations.