Add git to prerequisites in README

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Revise README

Change construction of some phrases, by removing direct reference to the
person reading a README.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
Fix documentation build problem on RHEL6

Texinfo 4 doesn't work with non-C locales and absolute paths to files. See
http://lists.gnu.org/archive/html/bug-texinfo/2010-03/msg00031.html for
details.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>