Add configuration option to pull haxe executable and extract/use that as bin.

[vantreeseba]

haxe.haxeVersion : 3.2.4,
haxe.someOtherBoolToUseDownloadedOne: true

Download from haxe server version specified.
If not exists, throw error.
Extract into local lib/bin/dir.
Check on startup if bin already exists and is correct version.