[patch] citeproc-js 1.0.52 compatibility patch

[fbennett]

With the processor now being good about quashing duplicate spaces, there is a problem with space-terminated RTF control words. This patch accomodates the replacement of terminal control words ending in a space, like "\i0 " and "\supersub ", with versions ending at an empty group, like "\i0{}" and "\supersub{}".

The patch is specific to processor version 1.0.52 and above, and should be applied together with that version of the processor.

[simon]

(In [6393]) update to citeproc-js 1.0.52
closes #1709: [patch] citeproc-js 1.0.51 compatibility patch: makeBibliography() return value
closes #1712: [patch] citeproc-js 1.0.52 compatibility patch

From Frank's notes for 1.0.52:

In this release, the following change may require accomodation
within the calling application:

The processor quashes double spaces in the output.
RTF control words can be terminated with a space, but
this causes an immediately following space to be lost
from the output. To avoid this, the RTF output mode of
the processor has been adjusted to terminate RTF control
words with {} rather than space. Applications that convert
processor output between other formats (such as HTML)
may need to be adjusted to accomodate this new behavior.

Also in this release:

Reverse the RTF-related conservatism in the quashing
of duplicate spaces that was introduced in 1.0.51.

Add missing parens to suspect test condition (not
related to any known bug).

From Frank's notes for 1.0.51:

The API return value changes slightly with this version:

For styles that have no bibliography element, the command
makeBibliography() now returns false, rather than a
stub bibliography object. Code adjustments in the
calling application may be required to accommodate
this change in behavior.

In other bibliography and citation returns, the processor
now provides new arrays, bibliography_errors and
citation_errors respectively, with information on
bibliography entries or cites that produce no meaningful
rendered output. Details are in the processor manual:

​http://gsl-nagoya-u.net/http/pub/citeproc-doc.html#handling-items-with-no-rendered-form

Also in this release:

Fix string breakage affecting text-case="title".

Fix over-aggressive quashing of spaces, which affected
spacing following RTF entities.