Create separate stages for optimising ABC and generating bytecode, so that the timestamps of these files differ for large projects

Previously an imported object file:
```
implementation module test.test

import code from "obj.o"
```

Would only search in the roots of the project paths. Now it will als
search in the test/ folder in the root.

Add EnvironmentByteCodePrelink and PrelinkByteCode options to prelink bytecode for use with the WebAssembly interpreter

in project files for modules in a directory write the directory once, instead of per module (to reduce problems caused by version control systems)

saveEnvironments (now saveEnvironmentsStupArg),
to reduce the number of GetFullApplicationPath calls in BatchBuild
  

use same separator characters in project and application relative paths in project files on all platforms,
add list of other paths containing project modules

fix removing of .exe in executable file name when converting a project from windows to another platform