bookmarks: move parse() and current() into property definitions

bookmarks: refactor code responsible for updates of bookmarks introduce _bookmarksupdate for common parts from commitctx and addchangegroup

bookmarks: repo._bookmarkcurrent should be a propertycache

bookmarks: write() can simply access repo._bookmarks

bookmarks: turn repo._bookmarks into a propertycache

Merge with stable

hook: fix bug (reuse of variable) introduced in 872d49dd577a For binary installs, the 'name' argument would be reused as a local variable, destroying its original value. The patch fixes that, and also avoids copying sys.path when it's not necessary.

patch: implement patch.eol=auto mode EOLs in patched files are restored to their original value after patching. We use the first EOL found in the file, files with inconsistent EOLs will thus be normalized during this process.