'packer' script: Fixes / General Updates and Improvements

[DavisDevelopment]

(to whom it may concern, this issue description is incomplete, and will be completed soon)

The 'packer' script (located in dist/) is currently not very up-to-date with regards to project structure and resource files. Other than the recent breaking changes to structure, there were already a number of features that were either completely broken (wouldn't successfully execute) or resulted in a broken app at runtime.

Current feature set:

• can handle compilation of haxe source
• can perform post-compilation, pre-execution (postprocessing) tasks
• automates application bundling to generate standalone executables (Windows & Linux)
• automates creation of application installers (Linux only)(Windows issue)