Cloudeebus via Crosswalk extension

The basic idea is this:
- run the Python side inside the Crosswalk extension process
- load the JavaScript side into Crosswalk from the extension
- replace the WebSocket communication with Crosswalk internal
  message passing

Because each app gets its own instance of Cloudeebus and thus its own
private connection to D-Bus, this solution does not suffer from the
security issues of the WebSocket-based Cloudeebus (circumventing D-Bus
access controls, services not seeing the real app).

On Tizen, the services see a normal app process talking to them via
D-Bus.

The Python side gets split it into the main executable using WebSocket
and the core engine which only uses objects providing certain
WebSocket APIs. The Crosswalk extension uses the engine with dummy
objects that map the WebSocket APIs to Crosswalk extension message
passing.
examples: usable with Crosswalk extension and web socket

When the browser already provides the "cloudeebus" module, then the
examples do not need (and shouldn't) import the cloudeebus .js again,
because that would replace the browser extension implementation with
the web socket version.
Send attributes of dbus commands with a certain dbus type. This makes it possible to send dictionary keys with other types than string
add engine.py to the scripts installed by setuptools

Otherwise, when Cloudeebus is installed as mentioned in the README
cloudeebus.py will fail to find engine.py at runtime.
agent server sample: un-comment autobahn and cloudeebus scripts inclusion
Fixed conversion of dbus types
Remove traces when decoding JSON arguments for dbus patterns
Merge branch 'typedkeys' into xwalk-merge
Applying JSON arguments dbus types parsing to cloudeebus engine.

Diffed engine.py@ab1b630 and cloudeebus.py@136c97d and patched
only the relevant changes.
Rename engine.py (too generic) as cloudeebusengine.py
make the Tracker example do an actual sparql query (dump classes and relations)
Update authors list. Crosswalk port is a major contribution.
bump version 0.6.1