changectx: if passing a basectx then exit __init__ immediately

basectx: return a copied context if changeid is already a basectx This implements a copy constructor so that we can pass a basectx-derived object in future refactorings.

basectx: add an empty class that will be used as a parent of all contexts At the moment, there is no simple way to check if an object is a context because there is no common parent class. If there were, we could use 'isinstance' everywhere. Simply having memctx inherit from workingctx or changectx would allow the use of 'isinstance' but that could lead to some confusing situations of reading the code since we have three distinct concepts of a context: - changectx represents a changeset *already* in the repo, and is therefore immutable - workingctx represents changes on disk in the working directory - memctx represents changes solely in memory which may or may not be on disk Therefore, I propose refactoring context.py to have all three contexts inherit from a parent class 'basectx'.

ui.config: fix bug in config alternatives from cc669e4fec95

proxy: allow wildcards in the no proxy list (issue1821)

hgweb: cleaner if conditions in changelog() function This removes unneeded extra nesting level and extra variable, which makes the code easier to understand.

hgweb: separate search itself and template generation This will make it simpler to add other search modes.

paper: remove unused occurence of changelogtag in views This variably isn't passed to these views and it always renders to empty string for this reason. Other themes don't have this issue.

hgweb: show full date in rfc822 format in tooltips at shortlog page The absolute date was not shown anywhere in the log view for users with enabled JavaScript.

hgweb: remove trailing whitespace in mercurial.js