Several bugs in the sample content generator and CsvBooks writer; new integrations test script

[mjordan]

In preparation for merging #424, I discovered a couple of bugs with the sample content generator script:

• the mappings files should map "Date taken" to <dateIssued>, not <dateCreated>
• the .ini Twig template should add shutdownhooks[] = 'php extras/scripts/shutdownhooks/create_structure_files.php' to .ini files generated for compound objects

And a bug in the CsvBooks writer:

• some cruft that is causing the toolchain to fail should be removed.

I discovered these glitches while writing a script that (optionally) clones and installs MIK and IIPQA, uses MIK to generate sample input for single file, compound, book, and newspaper content models, runs MIK on this sample input, and then runs IIPQA on MIK's output. This script is related to discussion in #385 about running test content through MIK separate from unit tests.

I'll open a PR to fix these issues and add the script to extras/scripts.

[MarcusBarnes]

Initially addressed in pull-request https://github.com/MarcusBarnes/mik/pull/427 (merged with commit https://github.com/MarcusBarnes/mik/commit/709037bd5a581685eb96d5df629d6c707868501a).