Merge pull request #22 from hholzgra/hartmut-DEL

consistently use DEL instead of rm in Makefiles
Addition of spinlock unit test
Misc fixes to doxygen comments
Updates for unit tests
Added rule version.h: $(ROOT_PATH)/VERSION
Merge branch 'master' of https://github.com/skysql/MaxScale
Merge branch 'Z2' of https://github.com/skysql/MaxScale into Z2

Conflicts:
	client/Makefile
	server/core/buffer.c
	server/core/test/makefile
	server/include/buffer.h
	server/modules/filter/Makefile
	server/modules/routing/webserver.c
Merge branch 'Z3' of https://github.com/skysql/MaxScale into Z3

Conflicts:
	gcov.diff
	server/core/buffer.c
	server/include/buffer.h
	server/modules/routing/readwritesplit/readwritesplit.c
Fix to bug http://bugs.skysql.com/show_bug.cgi?id=488. SHOW VARIABLES was treated as if it was session write command. Instead it is a read-only query. Changed to route that to master.
query_classifier.cc:skygw_get_canonical: Fixed bug in how strings were passed to replace_literal function. Changed to use item->str_ptr which stores all strings in the same way unlike item->name in which some string values have double quotation.
skygw_utils.cc:Fixed regexp so that it detects literals at the end of line too.
Cleanup
Fix to bug #510, http://bugs.skysql.com/show_bug.cgi?id=510, made every MaxScale thread to call mysql_thread_init() before entering poll_waitevents. Also main thread does this before starting services. Removed all calls to mysql_thread_init() and to mysql_thread_end() from elsewhere than from poll.c:poll_waitevents and from gateway.c:main

skygw_utils.cc: replace_literal: fixed memory leak
fir to TRG_ALL not working
Merge remote-tracking branch 'maxscale/Z3' into dev

Conflicts:
	gcov.diff
	server/modules/routing/webserver.c