[RFC v2 0/9] move more code into common/

[Tom Tromey]

This is a refresh of an earlier series to share more code between gdb
and gdbserver.

The original series is here:

    https://sourceware.org/ml/gdb-patches/2014-01/msg00747.html

Changes since version 1:
* Renamed new files to print-utils.[ch] (patch #1)
* Updated some comments in response to Yao's review (patch #2)
* Added missing _() markers (patch #2)
* Realized that I didn't remove newly shared declarations in patch #2;
  deleted them.

All other patches are, I believe, unchanged and approved by Pedro.

Tom