Add Environment to compilespec #24

Now compilespecs can define envs and have PACKAGE_NAME, PACKAGE_VERSION and PACKAGE_CATEGORY injected

pkg/compiler/artifact.go

@@ -21,6 +21,7 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
+
 	//"strconv"
 	"strings"
 	"sync"