fixes lichtner/fluentpdo#47
fixes lichtner/fluentpdo#43 - more generic implementation: allows
array() as parameter in all clauses. Although it does not cover column
aliases for arrays in (alias => column) form
Fix tabs
Update readme.md
Update readme.md
Refactoring shortcuts (BC break!)

UPDATE and DELETE queries can use short version of function update() and delete() but not with full where condition but only filter by primary key. If you need full where, than use where() function. It was too confusing.
Fix test 52
adding ability for Update Query ->execute()  to return the pdo statement
Minor formatting