Perl parser for the Kindle's 3 and 4 "My Clippings.txt" file

The myclippings script is based on parse_kindle_clippings script and parses
Kindle's "My Clippings.txt" file for highlights, notes, and bookmarks,
groups them by book/title, and stores them in the separate files or in a
single file.

Kindle's "My Clippings.txt" file is a mess.  The myclippings script helps to
sort clippings in order to process them in the editor or to store sorted and
edited clippings back in "My Clippings.txt" file.