Readable.java: Fix incorrect grammar in documentation.
Util.java: Added convenience read*Array[BL]E methods for native types.
Fix bug in 'readFrom' where file pointer was left changed on exception.

We should always try to seek back to the old file pointer, even when
there's an exception. Anything else would be a violation of the
semantics of SynchronizedReadableRandomAccessStream. So surround the
'read' statement with 'try {}' and put the final seek in a 'finally {}'
block.