prepare new PF: Temp
ready for branch? new postings format: TempBlock
metadata back
remove readTermsBlock from ReaderBase
fix multi thread bug: fully clone metadata
refactor Writer part
factor out writer d-gap to TermMetaData
use pad() instead of add() during flushTermBlock
add non-standard metadata.read()
refactor logic in metadata.read()
remove termBlockOrd, so that we're really non-block based api
always remember to call super.copyFrom
Merge branch 'dev' into trunk

Conflicts:
	lucene/core/src/java/org/apache/lucene/codecs/TermMetaData.java
	lucene/core/src/java/org/apache/lucene/codecs/temp/TempBlockTermsReader.java
	lucene/core/src/java/org/apache/lucene/codecs/temp/TempBlockTermsWriter.java
	lucene/core/src/java/org/apache/lucene/codecs/temp/TempPostingsReader.java
	lucene/core/src/java/org/apache/lucene/codecs/temp/TempPostingsWriter.java
revert API refactor on other codecs, so we have clean env to iterate