Added locale initialization from environment variables LC_ALL or LANG

[pesse]

Fixes #56

[jgebal]

Is there a chance to build a test to verify that NLS session parameters are by those environment parameters?

[pesse]

Hm, there is the possibility to check whether java-locale matches with NLS session parameters - but that would be testing JDBC driver, which is IMHO out of scope. All I did was setting java locale depending on environment variables.
A real system-test would be nice where you test running utPLSQL-cli in an environment with specific env variables and check for NLS session parameters then, but atm I don't have an idea how that could be achieved in a useful way.

Edit: I'll have a look at the failsafe-plugin for maven which allows integration tests. Might be what I'm actually looking for...