Do not allow negative runtime (due to clock skew) to be displayed

Also a minor readability improvement
Normalize formatting.
PTFM-11918 Java bindings don't retry non-retryable routes.

DXAPI.java now knows whether each route can be retried, and all other
clients e.g. apiCallOnObject also specify whether the request can be
retried.
PTFM-11917 Support 503/Retry-After in Python, Java bindings
PTFM-12009 Rename always_retry to safe_to_retry and update docs

This parameter rename better reflects the real meaning of the parameter.
always_retry has been deprecated and eliminated where possible. Changes
by language:

* documentation: update src/api_wrappers/README.md to show both names
* dxcpp: rename retry to safe_to_retry (non-breaking)
* dxpy: document always_retry but don't rename it as that would be
  breaking. Could be changed later if we provide compatibility
  translation
* dxjava: previously done
* ruby, R: no changes at this time, but could be changed later if we
  provide compatibility translation
* JS, Perl: no changes as these bindings have not implemented retry
  logic

Also: fix broken links in dxcpp doxygen.
Upgrade boost 1.53 -> 1.55 to fix UA build on Ubuntu 14.04

Building boost succeeds on Ubuntu 12.04 but fails in the atomic module
on Ubuntu 14.04. Seems to be this bug (fixed in boost 1.55) related to a
change in glibc:

  https://svn.boost.org/trac/boost/ticket/8973
  https://svn.boost.org/trac/boost/changeset/84950
Flip the symlink on the templates directory; add it to MANIFEST.in

This is needed to be able to properly distribute these resources with the PyPI package.
WIP
WIP
WIP