1. A big refactoring operation of all OS-related predicates.
The modules FILE_EXT and OS_EXT were relocated to PGC/OS and more modules were created, taking thematically related predicates from FILE_EXT and/or OS_EXT.
2. Safe deletion and renaming of files was added, using a trashcan directory in the user's home.

* [DATETIME_EXT,SC] New module for datatime predicates. From OS_EXT.
* [DIR_EXT,SC] New module for directory-related predicates. From FILE_EXT.
* [DIR_EXT,NEW] Added trashcan/1.
* [DIR_EXT,EXT] Changed delete_directory_contents/2 to safe_delete_directory_contents/2, using safe_delete_file/1 in FILE_EXT.
* [DIR_EXT,EXT] Improved and renamed assert_person_directory/0 and assert_personcal_subdirectory/1.
* [FILE_EXT,SC] New module for file-related predicates. From the old FILE_EXT.
* [FILE_EXT,NEW] Added create_file/1.
* [FILE_EXT,NEW] Added hidden_file_name/2.
* [FILE_EXT,NEW] Added safe_delete_file/1. This will be the new way to delete files, creating a backup in the personal directory.
* [FILE_EXT,NEW] Added safe_rename_file/2. Safe wrapper around rename_file/2.
* [FILE_EXT,NEW] Added spec_atomic_concat/3 which allows atomic content to be appended to the end of the inner atom of a file specification.
* [FILEPATH_EXT,SC] New module for file paths. From FILE_EXT.
* [INPUT_EXT,SC] New module for input (what's that?). From FILE_EXT.
* [IO_EXT,SC] New module for I/O-related predicates. From FILE_EXT and the old IO_EXT.
* [LOGGING,SC] Simplified the initialization process, using new predicates from DIR_EXT.
* [OS_EXT,SC] New module for OS-related predicates. From the old OS_EXT.
* [QLF_EXT,SC] New module for QLF-related predicates. Form FILE_EXT.
* [RDF_GRAPH,NEW] Added rdf_graph_copy/2 for copying graph. Simple wrapper for rdf_graph_merge/2.
* [RDF_SERIAL,FIX] Syntax error in rdf_load2/2.
* [RUN_EXT,SC] New module for running programs and scripts. From OS_EXT.
* [SHELL_EXT,SC] New module for shell-related predicates. From OS_EXT.
* [SWIPL_EXT,SC] New module for SWI-Prolog specific version checks and such. From OS_EXT.
* [TERM_EXT,SC] New module for terminal-extensions. Currently some simple ANSI stuff. From OS_EXT.
* [TTS_EXT,SC] New module for predicates for interfacing with existing TTS programs. From OS_EXT.