remove absolute_path() -- use resolve(). Add new functions.

Add functions

• get_username()
• get_owner()
• null_file()
• is_regular_file()
• hostname()
• getpid()
• get_permissions()
• java_version()
• java_api()

canonical(), resolve() add option expand_tilde (default true)

remove absolute_path() that duplicated resolve() functionality

use non-deprecated Java methods if available in JRE

add documentation for selecting JRE (optional)