explicit 1.6 language level
IDEA-122670 Hg log: request only necessary log information

*common hg parser for log command created;
*construct appropriate VcsCommit type using this HgBaseLogParser requesting only needed arguments from hg;
*HgLogCommand changed;
*annotations added;
*String.split method calls changed to StringUtil.split if possible;
*several parsing methods became package private and appropriate test moved to appropriate test package for getting access