Add checks to avoid NPE if not configuration defined for a device.
initial implementation of JPA persistence binding.
added jpa config values in openhab_default.cfg
fixes to transaction management in jpa persistence service. a new entitymanager is created and closed for each transaction.
only name refactorings.
some modification for a separate configuration class (as in db4o binding. This modularity will help in unit tests.
some refactorings. considering varchar uses 4 byte if empty made me switch to a one entity approach having a simgle value column which can take upto 200k.
minor simplifications.
Merge branch 'master' of https://github.com/mdbergmann/openhab
added first test.
reduced size of value column to 32k which is the max size for derby.
Merge branch 'master' of https://github.com/openhab/openhab
minor adjustments for Derby database in column size.
removed first test sqljpa binding reference in binding/pom.xml
Fixed bug causing repeated unsubscribes when item configurations are updated.

Signed-off-by: Davy Vanherbergen <davy.vanherbergen@gmail.com>
fix for duplicate key exceptions
fix isRaining
back button in greent does not work properly after the second usage.
#1183
Fix for MaxCube invalid settemperature when the actual temperature >25C
Revert "This adds a timeout to long polling requests for issue #765 .  The timeout is sent to the client as a header during the initial handshake.  I will make the timeout configurable in another PR."

This reverts commit 5996f5920bf343291910cc788c0c922fe4d71c62.
Revert "Fix for MaxCube invalid settemperature when the actual temperature >25C"

This reverts commit a04dac5db5ca72ec402d44733e30af56122c258a.