init CommandAgent
Add a setting for using locally installed Graphviz for generating diagrams.

The Google Charts service is only capable of rendering a limited range
of characters, so if you name your agents in an exotic language
generated diagrams are virtually useless being unable to make out.

With this change, Huginn embeds a locally generated SVG diagram instead
of relying on a third-party API if ENV['USE_GRAPHVIZ_DOT'] is set to a
command name/path of dot(1).

While at it:
- Use URI to compose a URL instead of hand-crafting it.
- Make the dot renderer a helper method.
CommandAgent whitespace+Open3 fix
Merge https://github.com/cantino/huginn
Merge pull request #224 from knu/graphviz_dot

 Add a setting for using locally installed Graphviz for generating diagrams.
Added basecamp agent
Merge pull request #228 from dsander/basecamp-agent

Added basecamp agent
add ALLOW_JSONPATH_EVAL option to .env
Added Hipchat Agent
Basecamp: ensure url encoding of http parameters

The since paramter is now passed to HTTParty which takes care of encoding it properly
Merge pull request #230 from dsander/hipchat_agent

Added Hipchat Agent
Merge pull request #231 from dsander/basecamp-encoding

Basecamp: ensure url encoding of http parameters
Modified website_agent to take an array of urls
Updated agent description
Merge pull request #234 from afro88/WebsiteAgentURLArrays

Website agent url arrays
Merge pull request #229 from cantino/add_optional_jsonpath_eval

Add ALLOW_JSONPATH_EVAL option to .env
Merge branch 'master' of https://github.com/ZirconCode/huginn into ZirconCode-master
refactor ZirconCode's Agent to only run when ENABLE_INSECURE_AGENTS is enabled in .env
Allow PostAgents to specify a default hash of data to be POSTed, as well as to be run periodically.
fix bug