Upgrade beautifulsoup4 to 4.6.3

[fabaff]

Description:

Changelog: https://code.launchpad.net/~leonardr/beautifulsoup/bs4

Example entry for configuration.yaml (if applicable):

sensor:
  - platform: scrape
    resource: https://home-assistant.io
    name: Release
    select: ".current-version h1"
    value_template: '{{ value.split(":")[1] }}'

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.