convert: handle copies when converting from Perforce (issue4744)

convert: add config for recording the source name This creates the convert.hg.sourcename config option which will embed a user defined name into each commit created by the convert. This is useful when using the convert extension to merge several repositories together and we want to record where each commit came from.

convert: support multiple specifed revs in git source This allows specifying multiple revs/branches to convert from a git repo.

convert: add support for specifying multiple revs Previously convert could only take one '--rev'. This change allows the user to specify multiple --rev entries. For instance, this could allow converting multiple branches (but not all branches) at once from git. In this first patch, we disable support for this for all sources. Future patches will enable it for select sources (like git).

monoblue: use padding instead of position for text in footer Some installations alter monoblue style and remove margins from body element (these margins have that dark gray background) to adapt hgweb instance to an already existing site design. However, the margins hid a quirk in page footer: a block of text needlessly popped out of the footer, and when margins were gone, the whole page got a vertical scroll bar because of that. Live example: https://hg.prosody.im/prosody-modules/ To remove the potential scroll bar, this block of text now uses left padding, which doesn't make it overflow the footer, but makes it achieve the otherwise same result visually.

monoblue: don't try to show repo on hgwebdir index page Index page shows a list of accessible repositories, it doesn't have a single-repo context.