Unified *_rcpath so the interface is similar across operating systems
Changed os_rcpath to combine system_rcpath and user_rcpath. Changed
system_rcpath and user_rcpath to both return a list of paths to add to the
combined rcpath for both Windows NT and other platforms.
hgwebdir: try to get web.style and web.motd from the ui.config system
This finishes fixing
issue253. As a bonus, web.style and web.motd
settings from ~/.hgrc will be used for the hgwebdir index page.