Added fetching of histories.

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#	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
#