Initial upstream fitlering implementation.

Test filter with up and down stream filtering. Keeps top N queries
and prints a report of these queries on session close.
Additional error checking and documentation.

Implementation of topfilter options
Updated QLA filter to allow for regex matches and client address matches
to control the statements that are logged.
Enhancements to topfilter and qlafilter

Documentation for topfilter and qlafilter
Improved diagnostics in filters
Merge branch 'develop' into MAX-65
Fixed bug in generation of execution time in report
Config fix
Merge branch 'develop' of github.com:skysql/MaxScale into develop

Conflicts:
	server/core/session.c
	server/modules/protocol/mysql_backend.c
	server/modules/routing/readwritesplit/readwritesplit.c

Resolved.

Addition of user in topfilter report and general tidyup
Merge branch 'develop' of github.com:skysql/MaxScale into develop