[PATCHv4] gitweb: PATH_INFO support improvements

[Giuseppe Bilotta <giuseppe.bilotta@gmail.com>]

Fourth version of my gitweb PATH_INFO patchset, whose purpose is to
reduce the use of CGI parameters by embedding as many parameters as
possible in the URL path itself, provided the pathinfo feature is
enabled.

The new typical gitweb URL is therefore in the form

$project/$action/$parent:$file..$hash:$file

(with useless parts stripped). Backwards compatibility for old-style
$project/$hash URLs is kept, as long as $hash is not a refname whose
name happens to match a git action.

The main implementation is provided by paired patches (#1#3, #5#6)
that implement parsing and generation of the new style URLs.

Patch #2 deals with a refactoring of the input parameters parsing and
validation, so that the rest of gitweb can be agnostic wrt to the
parameters' origin (CGI vs PATH_INFO vs possible other future inputs
such as CLI).

Patch #4 is a minor improvement to the URL syntax that allows web
documents to be properly browsable in raw mode.

Giuseppe Bilotta (6):
  gitweb: parse project/action/hash_base:filename PATH_INFO
  gitweb: refactor input parameters parse/validation
  gitweb: generate project/action/hash URLs
  gitweb: use_pathinfo filenames start with /
  gitweb: parse parent..current syntax from pathinfo
  gitweb: generate parent..current URLs

 gitweb/gitweb.perl |  392 ++++++++++++++++++++++++++++++++++------------------
 1 files changed, 254 insertions(+), 138 deletions(-)