Add documentation.
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+// Copyright 2013 Frank Schroeder. All rights reserved. MIT licensed.
+
+// Package properties reads Java properties files.
+//
+// Java properties files contain key/value pairs in one of the following form:
+//
+//   key = value
+//   key : value
+//
+// Whitespace around the delimiter is ignored which means that the following expressions are equal
+//
+//   key=value
+//   key= value
+//   key =value
+//   key = value
+//   key   =   value
+//
+// Blank lines and lines starting with '#' or '!' and are ignored until the end of the line.
+//
+//   # the next line is empty and will be ignored
+//
+//   ! this is a comment
+//   key = value
+//
+// If the delimiter characters '=' and ':' appear in either key or value then
+// they must be escaped with a backslash. Because of this the backslash must
+// also be escaped. The characters '\n', '\r' or '\t' can be included in both
+// key and value and will be replaced with their correpsonding character.
+//
+//   # key:1 = value=2
+//   key\:1 = value\=2
+//
+//   # key = value	with	tabs
+//   key = value\twith\ttabs
+//
+// Values can span multiple lines by using a backslash before the newline character.
+// All subsequent whitespace on the following line is ignored.
+//
+//   # key = value continued
+//   key = value \
+//         continued
+//
+// Java properties files must be ISO-8559-1 encoded and can have Unicode literals for
+// characters outside the character set. Both \uXXXX and \UXXXX are accepted.
+//
+//   # key = value with €
+//   key = value with \U20AC
+//
+package properties