Pass as much as possible in the single CompilerConfiguration instance instead
of in separate function parameters. Add corresponding keys to
JVMConfigurationKeys.
Re changes in compileModules: since output directory (stored now under the key
OUTPUT_DIRECTORY) is different for each module, the configuration of the whole
project is no longer applicable when compiling individual modules. Thus we copy
the project configuration for each module and add the output directory value
Part here means separate '.kt' file or multi-file facade
Now this memory optimization doesn't work with jar's,
because there is no simple way to write them incrementally.
Ilya Gorbunov