Autodetect --virtual-env and --sys-path from python.el settings.

Vars:
  +  jedi:import-python-el-settings.

Functions:
  + jedi:import-python-el-settings-setup.
Coding style fixes to previous commit.
Merge pull request #33 from fgallina/python-el-integration

Autodetect --virtual-env and --sys-path from python.el settings.