Change version on hscript dependency to 2.0

(which is compatible with haxe3)
Changes for haxe3

'@:macro' becomes 'macro'

Unused variable in switch case becomes '_'
Change unused variable to _

(haxe 3 switch changes)
Haxe3 compatibility changes
Merge pull request #12 from jasononeil/patch-1

Small patch for haxe3 RC compatibility