function ltrim( str ) {
	return replace( str, RE, '' );
}
Trims whitespace characters from the beginning of a string.

@private
@param {string} str - input string
@returns {string} trimmed string

@example
var out = ltrim( '   Whitespace   ' );
// returns 'Whitespace   '

@example
var out = ltrim( '\t\t\tTabs\t\t\t' );
// returns 'Tabs\t\t\t'

@example
var out = ltrim( '\n\n\nNew Lines\n\n\n' );
// returns 'New Lines\n\n\n'