git extractor: getPreviousRelatedCommits
git-extractor: calculators
git extractor: upd calculatePreviousFiles
git-extractor: rename calculators, PreviousRelatedCommitsCalculator
git-extractor: remove get files diffs
git-extractor: diff -> string in prevRelatedCommits
git-extractor: upd exception and graph tests
git-extractor: firstly print root in json
git-extractor: upd main, print prev related commits
git-extractor: bfs in prevRelatedCommits
git-extractor: bfs in history graph
Testing issue tracker integration: let's mention an issue, for example, TST-1
instantiate issue plugin manager on load
git-extractor: filter parents from related commits
found a way to
...determine if the commit is related to a bug issue
Merge branch 'issueTracker'

Conflicts:
	tcbpplugin-server/src/main/java/jetbrains/buildServer/bugprediction/AsyncBeanDataManager.java
git-extractor: fix bug in previous related commits
git-extractor: used checking in history graph, update main -> new json format, loading markup, refactoring
Merge branch 'git-extractor'