Propagating the desired execName (binary output name) for all phases.

The desired execName (user-provided binary output name) was not available for all phases, only during "compileGraph", calling the backend.
We needed it for an annotation plugin, which annotation processor is executed the Loaders "check-adl" phase.

Original behaviour:
- mindc/src/main/java/org.ow2.mind.AbstractADLCompiler#compile:119 called BasicADLCompiler#compileGraph which did: CompilerContextHelper.setExecutableName(context, execName);

Proposition:
- mindc/src/main/java/org.ow2.mind.AbstractADLCompiler#compile:74 calling BasicADLCompiler#initContext, doing the same, but earlier.

Note: I saw that our proposition is redundant with compileGraph (cleanup ?), and doesn't seem to handle the Target Descriptor case (contrary to the compileGraph method), however the latter seems non-functional since it computes an unused execName value, anyway. What do you think ?