Remove buildConnector()

Instead of storing the application url in an attribut
and having to call buildConnector() each time one of the components
is updated, use a GetUrl() method which will build the url.

As this method is not called often,
this shouldn't have any impact on the performances.
Remove the init method and move its content to the constructor.

Using the init method outside of the constructor will lead to a memory
leak, because the 2 pointers will not be deleted.

As the method is not required, I dropped it.
Remove useless checks
Merge pull request #11 from MiLk/fixes/init

Remove the init method and move its content to the constructor.
Merge pull request #13 from tokutake/develop

Fix typo.
Update libjson-rpc-cpp
Merge branch 'develop' into features/drop-buildConnector

Conflicts:
	src/mage.cpp
	src/mage.h
Make GetUrl() public
Update Makefile
Merge pull request #12 from MiLk/features/drop-buildConnector

Remove buildConnector()
Merge pull request #15 from MiLk/update-libjson-rpc-cpp

Update libjson-rpc-cpp
Merge branch 'develop' of https://github.com/tokutake/mage-sdk-cpp into develop