engine: remove checking of action from post filter
parser use xpt#parser#GetKeyType
f.test: set filetype=foo if foo.xpt.vim presents
fix: non-built default value should not move cursor to next

test 19-xset
Merge branch 'internal' into mix
Merge branches 'f.build', 'f.cases', 'f.conf', 'f.doc', 'f.docindex', 'f.engine', 'f.eval', 'f.filter', 'f.indent', 'f.log', 'f.once', 'f.parser', 'f.priority', 'f.pum', 'f.readme', 'f.replace', 'f.snipfunc', 'f.snpt', 'f.syntax', 'f.test', 'f.unittest', 'f.util', 't.sniptest', 'snp.cond-c', 'snp.cpp', 'snp.eruby', 'snp.html', 'snp.htmldjango' and 'snp.php' into mix
update doc