Support for scoped lime projects

[dpomier]

This put the foundation to set up lime projects within scopes. Meaning full support for lix, and more generally easier project switching. This PR requires openfl/hxp#18 to be merged.

Changes:

• new command lime scope create: create a directory .lime in the specified working directory.
• if existing, lime rebuild xxx will rebuild inside .lime. This ensures every lime project uses its own tools and dependencies. In consequence it is possible to rebuild tools and ndll files with lix, using different library versions from a project to another, and without rebuilding everything every time you switch projects.
• haxe, haxelib and neko command calls have been changed to allow them not being executables.

Every command that usually runs from the lime installation folder should run from the local directory .lime when existing: it replicates the same structure, allowing these commands to run the same way.

Things to be done / thought:

• test with the ci.
• test scoped projects with the ci.
• add .lime/settings.json or similar for scope info in version control, and automatically restore the scope with lime scope rebuild (or with lime setup?). This might come in another PR.
• anything else?

[hansagames]

Hi @dpomier any progress on this ? :)