add a missing experimental config option $default_markup
simplified em-strong routine to render nested em-strong cases correctly
WantedPages macro plugin: check #format pi correctly
Table parser: fix to support <=> as table header attribute
fixup table parser

 * count left/right spaces to set alignment more naturally
 * strip last CR for multiline cell
 * strip the first space conditionally to prevent from indent
remove undocumented features
remove NoSmoke compatible tags and replace it with $trtags option.
bump up version to 1.2.3-RC4
fixup for new cache class
check compatible issue using "===" operator
fixup to accept rowbgcolor etc.
fixup get_instruction() and trash PI instructions to hide PIs correctly.

processors do not know PI instructions