Added possible for get more virtual usages then one

- Move cailometer plugin
- Modified collects virtual plugi for getting more usages
Move cailometer tests and added tests for collets virtual plugin

- Move cailometer plugin tests
- Added collets virtual plugin
Fix tests

- Fix tests
Added empty VIRTUAL_VENTURE_NAMES to app.py

- Added empty VIRTUAL_VENTURE_NAMES to app.py
Merge branch 'develop' into feature/add-xenservers

Conflicts:
	src/ralph_pricing/app.py
	src/ralph_pricing/plugins/collects/virtual.py
Fix tests and merge with develop

- Fix tests
Merge pull request #112 from kula1922/feature/add-xenservers

Added possible for get more virtual usages then one