fix duplicated ph focusing bug for Build()

bug that ph will be choosed twice:
XPT b
XSET x|post=Build('`ph^-`ph^')
`x^
fix mark escaping
add test 60-ph-func-Build-def
add test 60-ph-func-Build-instant
add test 60-ph-func-Build-post
add mark functions
fix
fix
fix
from 023576d use v2 engine
warn to info for v1 engine
fix xptemplateTest.vim
autoload/xpt/flt.vim
autoload/xpt/ftsc.vim
autoload/xpt/group.vim
autoload/xpt/ng.vim
autoload/xpt/parser.vim
autoload/xpt/ph.vim
autoload/xpt/phfilter.vim
autoload/xpt/rctx.vim