Revert "add log replace color"

This reverts commit 8ef27f0bb3.

examples/log.v

@@ -1,12 +0,0 @@
-import log
-
-fn main(){
-    mut l := log.Log{level:log.INFO}
-    l.i('info')
-    l.w('warn')
-    l.e('error')
-    l.d('no debug')
-    l.set_level(log.DEBUG)
-    l.d('debug')
-    l.f('fatal')
-}