[#2665] Implement SPI for RenderContext and BindContext listening to
allow for custom SQL transformation

 * Fixed semantics of UPDATE clauses
 * Added an UPDATE WHERE test case
Merge branch 'master' of git@github.com:jOOQ/jOOQ.git

Conflicts:
	jOOQ/src/test/java/org/jooq/test/VisitContextTest.java