SELECT permission not needed for SHOW STATUS
support connecting without binding to a particular db

without this patch:
[2014-01-24 16:06:26,030] [Thread-1] MySQLCollector couldnt connect to
database (1044, "Access denied for user 'diamond-coll'@'127.0.0.1' to
database 'helloimadb'")

with this patch:
profit !!
add a test for error throttling
initialize config variable
Add additional metrics to Apache httpd collector.

This allows the Apache httpd collector report additional metrics about
workers by parsing the "Scoreboard" from mod_status; previously, the
Scoreboard was ignored.

In addition to reporting "IdleWorkers", the collector now reports
metrics for: 'StartingWorkers', 'ReadingWorkers', 'WritingWorkers',
'KeepaliveWorkers', 'DnsWorkers', 'ClosingWorkers', 'LoggingWorkers',
'FinishingWorkers', and 'CleanupWorkers'
Merge pull request #519 from Lacrymology/error-throttling-fixes

Error throttling fixes
Modify build_doc.py
Merge pull request #521 from dongweiming/modify_build_doc

Modify build_doc.py
Merge pull request #520 from jswank/master

Add additional metrics to Apache httpd collector
Merge pull request #517 from Dieterbe/mysql_collector

Mysql collector
Merge branch 'master' of github.com:BrightcoveOS/Diamond