remove invalidateByTriple+tests; small refactoring
start implementing transaction infrastructure

mostly without test functions
wrote tests to check transaction with one operation

covered operations:
+ rememberQueryResult
+ invalidateByGraphUri
+ invalidateByQuery
add test which executes two operations in a transaction
Merge branch 'master' into transactions
Update forgotten test/config.ini.dist
Huge improvement for transaction support in QueryCache

From now on, each QueryCache entry has one more field
named "relatedQueryCacheEntries", which contains the
ID of another QueryCache entry representing a list of
related QueryCache entries, if they are available.

These entries are related to an entry, if they were
part of a sub transaction. And each of these are also
linked to each other.

Gets one invalidated (by query or URI), all of them
getting invalidated too.
Small refactoring
add test to check indirect invalidation of QueryCache entries
Add functionality + test for invalidation inside a running transaction
Shorten function parameter name (checkIfTransactionIsActive -> checkTransaction)
Implement a more flexible architecture for cache adapters

They all have to implement the according Base interface.
add basic tests to backup Cache class