color: move '_colormode' to the core 'ui' class Having all 'ui' objects aware of 'color' allows us to update the core code to handle color. The mode will stay 'None' in the default case so that will not introduce any changes.

hgweb: explictly pass basectx in webutil.diffs There's only one case where `basectx` parameter is None (over two usages), so it's probably not worth handling the special case as it makes code-reading harder. Along the way, use ctx.p1() instead of checking for ctx.parents() being empty which should not occur.

serve: mark --stdio and --cmdserver as "(ADVANCED)" flags This will hide them from the default --help output.

help: hide command line options marked as "advanced" Previously, we have keywords like "(DEPRECATED)" and "(EXPERIMENTAL)" to hide command line options in non-verbose help output. However, sometimes an option is neither deprecated nor experimental. It's well-tested and working, but just not designed to average users. This patch adds a keyword "(ADVANCED)" to fit in such use cases. Thanks rom1dep for the suggestion of the word "advanced".

pager: do not try to run an empty pager command If pagercmd is explicitly set to '', the pager process would exit silently and the output would be lost. We'd better disable the pager in such case.

graphlog: restore pager lost at 1cec1d863008

gitweb: add "more" and "less" navigation links in filelog template

context: also return ancestor's line range in blockancestors

context: add a followfirst flag to blockancestors

py3: use pycompat.fsencode() to convert __file__ to bytes __file__ returns unicodes on Python 3. This patch uses pycompat.fsencode() to convert them to bytes.