Merge pull request #3 from vaibhavbsharma/master

Framework implementation for openat(2), getsockopt(2), setsockopt(2), shutdown(2)
Merge pull request #4 from vaibhavbsharma/master

Framework implementation for setgroups32(2), bug fix in getgroups32(2)
Updates to INSTALL file and STP patch

Based on suggestions from Mathias Payer, though he may have had
some simpler fixes in mind.
- Update list of Debian/Ubuntu packages to show a minimal needed set,
  and for 14.04.
- Recommend Git STP over SVN STP, but also update the SVN STP patch
  with a 14.04 compatibility fix.
Add a -concolic-file option

Another point in the large space of possible options of specifying
symbolic inputs. E.g., like -symbolic-file, but with the difference
between -symbolic-string and -concolic-string.
Disable the c.e. cache for -solve-final-pc

Since a major use of -solve-final-pc is to make sure that the final
query is the one for the whole path.
Start jump hooking, add -trace-callstack

Implement a relatively general mechanism for hooking jumps.
Use it to implement a new -trace-callstack option, which is like an
improved version of the old -print-callrets (which has been removed).