Changed caching policy: now hosts are not cached. Fetcher became non-static and more concise.
Slightly changed javadocs: added @since clause.
Code refactored. Added fetching of additional information about host.

# Please enter the commit message for your changes. Lines starting
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# On branch master
# Changes to be committed:
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#	modified:   src/main/java/ru/webeffector/Fetcher.java
#	modified:   src/main/java/ru/webeffector/ServiceDocument.java
#	modified:   src/main/java/ru/webeffector/Webmaster.java
#	modified:   src/main/java/ru/webeffector/host/Crawling.java
#	modified:   src/main/java/ru/webeffector/host/CrawlingDenialDetails.java
#	modified:   src/main/java/ru/webeffector/host/CrawlingState.java
#	modified:   src/main/java/ru/webeffector/host/DateTimeAdapter.java
#	modified:   src/main/java/ru/webeffector/host/History.java
#	modified:   src/main/java/ru/webeffector/host/Host.java
#	new file:   src/main/java/ru/webeffector/host/IndexInfo.java
#	modified:   src/main/java/ru/webeffector/host/Stats.java
#	modified:   src/main/java/ru/webeffector/host/Verification.java
#	modified:   src/main/java/ru/webeffector/host/VerificationRefusalDetails.java
#	modified:   src/main/java/ru/webeffector/host/VerificationStatus.java
#	modified:   src/test/java/ru/webeffector/WebmasterTest.java
#