support for XZ.Cache;

clarified modules;

clarified use of XML.Cache;

clarified multi-line properties;

clarified modules;

discontinued unused / untested distinction of separate PIDE modules;

more operations (see also properties.ML);

clarified modules;

more operations (like Markup.parse_bool in ML);

more compact representation of special string values;

tuned signature (again) -- keep Properties more generic;

tuned signature;

include timing properties in log;
general Properties.parse operations;
tuned signature;

prefer general Properties.Value.Boolean;

tuned signature;

separate compilation of PIDE vs. Pure sources, which enables independent Scala library;

explicit indication of modules for independent Scala library;

more uniform Properties in ML and Scala;