Chartmaker version 1.53

Release 1.53:
This release fixes a bug when generating mbtiles databases and includes all of the items from release 1.52.

Release 1.52:
This release fixes a bug when processing the Caribbean VFR charts. The FAA added a new planning chart to the zip download file that has no wsgbounds metadata, which this application needs in order to add that metadata to the resultant mbtiles database. For now, that planning chart is ignored and not processed.

This release has added a new timezone setting in settings.json, so that timing log output will be properly formatted to the indicated time zone. See https://en.wikipedia.org/wiki/List_of_tz_database_time_zones for an exhaustive list of valid time zone values. The default time zone value is "America/Chicago" because I live in the US Central time zone. A few examples of other valid values would be "America/New_York" for Eastern, "America/Denver" for Mountain, "America/Los_Angeles" for Pacific, "America/Alaska", etc. If this value is an empty string, the timing output will be Greenwich Mean Time.

This release has also added a new debug true/false setting, which if set to true, will output STDOUT from the execution of the various GDAL functions. The default value is true.

This release has implemented simple parallel processing in the tile merging process by incorporating Parallel::ForkManager in the mergetiles.pl Perl script, specifically where the process is iterating through all of the zoom levels to merge duplicate tiles.

The Docker image at https://hub.docker.com/repository/docker/n129bz/chartmaker has also been updated with this release.