[KDev4] buildtools/builder API suggestion.

[dukju ahn]

I'm working on CustomMakeManager. The problem is that
IProjectBuilder::build() api is not reusable for CustomMakeManager

in IProjectBuilder, the only interfaces are

    virtual bool build(ProjectBaseItem *dom) = 0;
    virtual bool clean(ProjectBaseItem *dom) = 0;

The problem is that we cannot specify build target or
build directory using ProjectBaseItem. If we see the implementation
in MakeBuilder::build(), dom is casted into ProjectItem, which
doesn't contain any information of target or build directory. So
MakeBuilder just executes "make" with no target in top project dir.

Why don't we specify targets as an additional argument?