Some refactoring and fixed more specs working with transactions #94

Need to refactor the rspecs, which rspec tests which layer  ? Are there any duplication of tests ?

Still 8 rspec that does not work running with a transaction (node_auto_tx.rb). Before 15 specs did fail.
Impl. nested transactions #94
Enabled more tests for  nested transactions #94
Use neo4j 2.1.3 on travis
Fixed open struct problem for JRuby
Wrote some specs for transactions, does fail on jruby #94
Had to wrap Embedded Neo4j transaction in ruby object because of bug in java api #94

See discussion https://groups.google.com/forum/#!topic/neo4j/w1L_21z0z04
Some refactoring, shared behaviour for embedded and server transactions #94

* Made Neo4j::Transaction a module instead of a class
* Removed success method
* Renamed finish to close
Implemented acquire_read_lock and acquire_write_lock for transaction #94
Fixed bug on Neo4j::Relationship.props for server db #94
changes needed for activerel
Merge pull request #98 from subvertallchris/transaction

changes needed for activerel
Merge pull request #97 from andreasronge/transaction

Better support for transaction
release 3.0.0.alpha.19