Cleanup unused variables

xiphux commit adaptation, almost no conflicts, except GitPHP_GitLog
fix memory issue with blobs (squashed commit)

888c324 Don't retain large blob data in memory
4605d85 Calculate binary flag and size when loading blob data
217fcd5 Don't load full data to determine blob size
1db9eba Share blob size loading code
ab1c8df Don't put large blob data in objectcache
471d492 Cache blob size
2ae516f Cache whether a blob is binary
29466d0 Move blob size loading to strategy

Signed-off-by: Chris Han <xiphux@gmail.com>

Note: this was the main reason of googlebot restriction
My T1 server with only 2GB of memory was overloaded by blobs load
generated by google-like bots

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>
Pack: sanity checks for invalid data/idx objects files

useless but to remember (already made in ObjectLoader)
Enable required repo options by default
robots: use a config var to skip the restriction

gitphp-repo is made to handle huge projects like AOSP or CyanogenMod
dont bother android developpers with robots.txt headaches

use redirections to allow access of commit diffs

and add the GITPHP_CONFIGDIR define to tests init...
history: handle the plain/patch output for git diff