Crawler should follow the robots meta tag rules

The web crawler does obey robots.txt files, but not the robots meta tag rules. If a document has the following meta tag included, the crawler just ignores and fetches it anyway:
<meta name="robots" content="noindex, nofollow" />

I would recommend that the following changes are done in order to improve the crawler if one of the "Obey robots.txt ..." options is set:

1. <meta name="robots" content="noindex, nofollow" />

• do not fetch the document at all

2. <meta name="robots" content="noindex, follow" />

• only follow the other links in this document

3. <meta name="robots" content="index, nofollow" />

• fetch the document, but do no follow any link in it.

4. Change most of the text that appear on the page for robots option settings to something like:
"Robots.txt usage" => "Robots.txt and Robots <meta> tag usage"
"Don't look at robots.txt" => "Ignore robots settings"
"Obey robots.txt for data caches only" => "Follow robots rules for data caches only"
"Obey robots.txt for all fetces" => "Follow robots rules for all fetches"