boost 7.x-1.0-beta2

New features and improvements:

* #1448476: Admin status block in 7.x-1.x - basic admin block for cache status and flush (bgm)
* #1666140: Boost API: hook_boost_is_cacheable: have a way to know if the current page is cacheable for the status block - API change to hook_boost_boost_is_cacheable() for the "cache status" block.
* #1717506: Improve core cache documentation [was: No cached pages are generated or served] (soundstripe)
* #1386166: PDOException with UTF-8 aliases / boost does not cache pages with UTF-8 aliases - improve caching of pages with UTF-8 url aliases (imoreno, bgm) - may need more work?
* #1074080: Cron crawler in 7.x? - minimal crawler / page cache refresh (bgm) - known bug: requires the latest "dev" version of the "expire" module (newer than 7.x-1.0-alpha3)

Bug fixes:

* #1612448: Don't use block module constant (jchatard)
* #1616356: Boost Module problem in logged in user (jchin1968)
* #1642234: [function.rmdir]: Directory not empty in _boost_rmdir() (mikeytown2)
* #1653206: Warning: array_shift() expects parameter 1 to be array, string given in boost_boost_menu_router() also for Panels (Shnapoo)

Thanks to all contributors who have helped reporting/fixing issues and provided support in the issue queue.