Support arquillian. prefix in configuration properties

Story:

In order to have more readable and intuitive property names
As a tester
I want to be able to use the arquillian. prefix to configure properties, or no prefix if the properties are specified in an arquillian.properties file

Scenario:

Given that I define a system property or a property in arquillian.properties which uses the prefix arquillian. instead of arq.
When Arquillian loads the configuration
Then the property should be recognized

Given that I define a property in arquillian.properties which does not use an arquillian-specific prefix
When Arquillian loads the configuration
Then the property should be recognized

Rationale:

The arq. prefix may be convenient for some, but to newcomers it's cryptic. We should support both the shorthand (arq.) and the full prefix (arquillian.) when loading properties.

Since the property matches are done using regular expressions, it should not be hard to add support for both prefixes.

I also recommend allowing extension to be abbreviated "ext". Thus, to configure webdriver, I could use any of these property declarations:

arquillian.extension.webdriver.browserCapabilities=firefox
arquillian.ext.webdriver.remoteReusable=true
arq.ext.webdriver.remoteAddress=http://127.0.0.1:4444/wd/hub/

Since we are reading properties from an arquillian.properties file, we could prepend the arquillian. prefix automatically, thus making it optional.

extension.webdriver.browserCapabilities=firefox

The prefix is really only needed for system properties, which need the qualified namespace.