compileValue(), added convertion of hexadecimal-color output value to
short notation when possible. For example, #003399 => #39, #000000 =>

Conflicts:
	lessc.inc.php

(before closing curly brace) ...in "compressed" output mode of
formatter.

...around string literals that contain neither PHP variables to
interpolate nor special characters like \n. Strings wrapped in single
quotes are processed slightly faster in PHP since, unlike strings
wrapped in double quotes, PHP variables are not interpolated at all in
strings wrapped in single quotes and only two characters that must be
escaped in single-quoted strings are single quote character itself and
`\` character.