Add a change log interface for svn_authz, can compare each svn_authz revision.

[jiangxin]

Add a change log interface for svn_authz, can compare each svn_authz revision.

• add Log in menu;
• the default log page display svn_authz modification history;
• user can compare each revision of svn_authz file.

[jiangx]

(In [29]) See #7: add get_logs, get_page_logs method to RcsLog? class.

[jiangx]

(In [30]) See #7: add cat, differ function.

[jiangx]

(In [31]) See #7: add logs controller to display logs.

[jiangx]

(In [33]) See #7: chinese i18n for logs.

[jiangx]

(In [34]) See #7: New paginate strategy; add log_per_page to config file.

[jiangx]

(In [35]) See #7: compare revisions in logs page.

[jiangx]

(In [36]) See #7: admin can rollback to history revision from log page.

[jiangx]

(In [37]) Fix #6 & #7: upgrade to 0.1.3: backup using rcs; logs support;

[jiangx]

(In [38]) Fix #7: bugfix: remove -L option from rlog command; add templates for rollback view.

[jiangx]

(In [39]) Fix #7: disable rollback button for latest revision.