Add knobs to enable/disable files/lines changed in log view

These columns can cause lots of IO on the server, so add settings to
explicitly enable them. Also, add per repo settings to optionally disable
the columns if sitewide enabled.

While at it, do not allow repo.snapshot to enable snapshots if the global
setting is disabled.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgitrc

@@ -12,6 +12,14 @@
 #snapshots=0
 
 
+## Enable/disable display of 'number of files changed' in log view
+#enable-log-filecount=0
+
+
+## Enable/disable display of 'number of lines changed' in log view
+#enable-log-linecount=0
+
+
 ## Specify a root for virtual urls. This makes cgit generate urls like
 ##
 ##    http://localhost/git/repo/log/?id=master
@@ -97,4 +105,6 @@
 #repo.path=/pub/git/cgit
 #repo.owner=Lars Hjemli
 #repo.snapshots=1				# override a sitewide snapshot-setting
+#repo.enable-log-filecount=0			# override the default filecount setting
+#repo.enable-log-linecount=0			# override the default linecount setting
 #repo.module-link=/git/%s/commit/?id=%s		# override the standard module-link