The previous attempt to handle unexpected markers in the data stream caused breakage...

The previous attempt to handle unexpected markers in the data stream caused breakage in applications that attempted to set bytes_in_buffer to a larger value than the actual size of the JPEG image.  The latter behavior was causing the fast decoder to be used for the last MCU in the image under certain circumstances, and this sometimes caused the EOI marker to be encountered by the fast decoder, which was treating it as an "unexpected" marker and throwing an error.  Now, the fast decoder simply hands off the decoding of the block to the slow decoder if any marker is encountered.

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@584 632fc199-4ca6-4c93-a231-07263d6284db