gitweb: ViewVC-like "tree_blame" view

This series is a bit fixed up and a tiny bit cleaned up version of "Gitweb caching v7" series from John 'Warthog9' Hawley:
http://thread.gmane.org/gmane.comp.version-control.git/160147

This series is based on top of 'next', because it contains 'jn/gitweb-test' branch.

The difference from v7.2 is that it takes into account 'test-installed' target in gitweb/Makefile in first patch of its series, and that testing of caching support is slightly extended. Note that some of those tests fail currently, not because of error in gitweb caching code, but because I was not able to disable calling cacheWaitForUpdate(), which hinders testing.

Those differences were also described in "Re: What's cooking in git.git (Nov 2010, #01; Tue, 9)":
http://article.gmane.org/gmane.comp.version-control.git/161309

Table of contents:
==================
[PATCHv7.2 1/4] gitweb: Prepare for splitting gitweb [PATCHv7.1 2/4] gitweb: add output buffering and associated functions [PATCHv7.1 3/4] gitweb: File based caching layer (from git.kernel.org) [PATCHv7.2 4/4] gitweb: Minimal testing of gitweb caching

Shortlog:
=========
Jakub Narebski (2):
gitweb: Prepare for splitting gitweb
gitweb: Minimal testing of gitweb caching

John 'Warthog9' Hawley (2):
gitweb: add output buffering and associated functions
gitweb: File based caching layer (from git.kernel.org)

Diffstat:
=========

 gitweb/Makefile                           |   20 ++-
 gitweb/gitweb.perl                        |  134 +++++++++++-
 gitweb/lib/cache.pl                       |  348 +++++++++++++++++++++++++++++
 gitweb/static/gitweb.css                  |    6 +
 t/gitweb-lib.sh                           |   15 ++
 t/t9500-gitweb-standalone-no-errors.sh    |   20 ++
 t/t9501-gitweb-standalone-http-status.sh  |   13 +
 t/t9502-gitweb-standalone-parse-output.sh |   33 +++
 8 files changed, 579 insertions(+), 10 deletions(-)
 create mode 100644 gitweb/lib/cache.pl

1.7.3