Releases for Abstractions

- Fixes a bug with the return value of cache_function_array_result().
- Adds generate_php_extension_requirement() and abstracts generate_library_requirement() to _generate_requirement().
- Docs fix.
- Adds generate_library_requirement() function.
- Adds curry() function.
- Adds flip() function.
- Adds pernament_cache_function_result().
- Adds array_sort() function.

First release.