Slow compilation time in a big project. What branch contains Incremental Compilation?

[jmgomez]

@hlaaftana We are using ORC. But I guess we could make the plugin work with 
None, after all the only ref types we use are strings and seq. Unreal has its 
own GC. However, even with mm:none IC fails for a hello world with this trace:
    
    
    
    G:\NimSources\Nim\compiler\nim.nim(150) nim
    G:\NimSources\Nim\compiler\nim.nim(103) handleCmdLine
    G:\NimSources\Nim\compiler\cmdlinehelper.nim(57) 
loadConfigsAndProcessCmdLine
    G:\NimSources\Nim\compiler\nimconf.nim(260) loadConfigs
    G:\NimSources\Nim\compiler\scriptconfig.nim(224) runNimScript
    G:\NimSources\Nim\compiler\passes.nim(186) processModule
    G:\NimSources\Nim\compiler\passes.nim(76) processTopLevelStmt
    G:\NimSources\Nim\compiler\sem.nim(669) myProcess
    G:\NimSources\Nim\compiler\semdata.nim(586) storeRodNode
    G:\NimSources\Nim\lib\system\fatal.nim(53) sysFatal
    Error: unhandled exception: index out of bounds, the container is empty 
[IndexDefect]
    
    
    Run