bin:

Moved the openquake and oq_create_db scripts to openquake.engine.bin.
bin:

Added __init__.py to bin module.
packager.sh:

Updates to package script after some things have been rearranged in
bin/ and openquake/engine/bin.
tools/test_migration.py:

Replace create_oq_schema with oq_create_db.
bin:

Added symlink to openquake/engine/bin/openquake and oq_create_db.
bin, packager.sh, openquake/engine/bin:

Moved `openquake` to `oqscript.py` and update bin/openquake
symlink.

Also removed a `mv` statement from the packager script.
Merge pull request #1261 from larsbutler/setup-py-and-bin-folder-fix

Fix for installing source code via pip/git

[r=nastasi-oq] [f=*trivial]