#1464: bind custom PMP area names as values

[gemshrine]

Fixes #1464.

Custom area names were interpolated into both XPath and Factbase expressions. An apostrophe could break the XML lookup before the property query, and quotes or backslashes could also change how the Factbase parser read the area value.

The XML lookup now binds its area name as an XPath variable. Factbase queries bind $area through their parameter context, and property listing uses that same bound enumeration. No area-name characters need to be interpreted as query syntax.

The regression reads values and property lists for custom areas containing an apostrophe, a double quote and a backslash, and checks that those names remain present in areas. The PMP tests passed: 24 tests, 57 assertions. RuboCop passed for both changed files with the lockfile's rubocop-elegant 0.5.1, and git diff --check passed.

[gemshrine]

Duplicate of #1365, which already fixes the custom PMP area lookup bug reported in #1322. Issue #1464 has been closed as a duplicate of that original report.