Patch breakpoints so it doesn't make cache clear slow on sites with enabled themes not using breakpoints

I confirm patch #1 works. Thanks @hefox :)

This one seems like a nice quick win! Adding to the sprint board

Note: This was a patch applied to our project, not vanilla Panopoly or OA2.

Ok, so when running drush cc all without patch:

Loaded alias @platform_develop from file /var/aegir/.drush/platform_develop.alias.drushrc.php [10.05 sec, 71.18 MB]
Calling hook drush_cache_command_clear [10.07 sec, 71.23 MB]
Calling drush_cache_clear_both() [10.08 sec, 71.3 MB]
'all' cache was cleared. [59.7 sec, 157.86 MB]
Returned from hook drush_cache_command_clear [59.7 sec, 157.85 MB]
Command dispatch complete [59.7 sec, 157.79 MB]
 Timer  Cum (sec)  Count  Avg (msec) 
 page   59.329     1      59329.19
Peak memory usage was 166.45 MB [59.7 sec, 157.79 MB]

Second time, with patch!

Loaded alias @platform_develop from file /var/aegir/.drush/platform_develop.alias.drushrc.php [11.99 sec, 71.17 MB]
Calling hook drush_cache_command_clear [11.99 sec, 71.23 MB]
Calling drush_cache_clear_both() [12 sec, 71.3 MB]
'all' cache was cleared. [60.22 sec, 157.86 MB]
Returned from hook drush_cache_command_clear [60.22 sec, 157.86 MB]
Command dispatch complete [60.22 sec, 157.8 MB]
 Timer  Cum (sec)  Count  Avg (msec) 
 page   59.838     1      59838.38
Peak memory usage was 166.45 MB [60.22 sec, 157.8 MB]   

I didn't notice differences, but I do like the fact it's properly invoking menu rebuilds in the patch, instead of calling it directly. So RTBC!

Looking the upstream issue and the people who worked on it (Dave Reid, sylus, hefox, quicksketch) and how far it got, I'm going to commit it even if we can't reproduce the problem/fix personally. Clearly some really bright people see this problem and this solution works for them. Committed!