Add inheritence in Continuum profiles

http://docs.codehaus.org/display/CONTINUUM/CI+profiles

Continuous Tools Installations
In some case, users need to use different tools (jdk, maven, ant...) to build all projects added to Continuum.
It would be useful to add some screens to configure them

Continuous Profiles
A Continuum Profile is a preconfigured environment to use with a build definition. It is composed of a set of installation, ie. Maven version + JDK Version

If a profile isn't complete for the build (for example, the maven version isn't set), Continuum will use the mvn found in the PATH like it does it actually.

The user will add a continuum profile to a build definition if he want to change default tool to use.

Optional features
1. To simplify the Continuum configuration, I think it would be good to move build file, scheduler choice and the SCM policy from the build definition to the profile. With that, the user will configure one time the profile and will can reuse it in all build definitions without redefine the configuration everywhere (for example if he want to run 'clean deploy' in all build definition instead of 'clean install').

2. If 1) is implemented, we should add the possibility to add inheritance in profiles so the user we'll can define a set of profiles like that:

profile 1 : Maven 2.0.6 + JDK 5
profile 2 : profile 1 + build file=pom.xml
profile 3 : profile 2 + schedule=run_hourly
profile 4 : profile 2 + schedule=nightly + scm_policy=clean_checkout
3. With 2) implemented, we'd can add the notion of combined profiles like my_combined_profile = profile3 + profile 4. With this feature, we'd can remove the build definition feature from continuum, the user would add a combined profile to the project/project group without configuration and automatically, the project/project group would be configured to run hourly with a SCM update and nightly with a clean checkout.