settings: enable regexes by default and add support for perl syntax

NEWS

@@ -15,6 +15,8 @@ ncmpcpp-0.7 (????-??-??)
 * Current MPD host may now be shown in playlist (playlist_show_mpd_host configuration variable, disabled by default).
 * Random album artists can now be added to the playlist.
 * Case insensitive searching is now Unicode aware as long as boost was compiled with ICU support.
+* Searching with regular expressions are now enabled by default.
+* Support for the Perl regular expression syntax was added.
 
 ncmpcpp-0.6.3 (2015-03-02)
 

doc/config

@@ -432,9 +432,9 @@
 #
 #display_remaining_time = no
 #
-## Available values: none, basic, extended.
+## Available values: none, basic, extended, perl.
 ##
-#regular_expressions = none
+#regular_expressions = basic
 #
 ##
 ## Note: If below is enabled, ncmpcpp will ignore leading

doc/ncmpcpp.1

@@ -287,7 +287,7 @@ If enabled, bitrate of currently playing song will be displayed in statusbar.
 .B display_remaining_time = yes/no
 If enabled, remaining time of currently playing song will be be displayed in statusbar instead of elapsed time.
 .TP
-.B regular_expressions = basic/extended
+.B regular_expressions = none/basic/extended/perl
 Type of currently used regular expressions.
 .TP
 .B ignore_leading_the = yes/no

src/settings.cpp

@@ -578,10 +578,12 @@ bool Configuration::read(const std::vector<std::string> &config_paths)
 			regex_type = boost::regex::basic;
 		else if (v == "extended")
 			regex_type = boost::regex::extended;
+		else if (v == "perl")
+			regex_type = boost::regex::perl;
 		else
 			throw std::runtime_error("invalid argument: " + v);
 		regex_type |= boost::regex::icase;
-	}, defaults_to(regex_type, boost::regex::literal | boost::regex::icase)
+	}, defaults_to(regex_type, boost::regex::basic | boost::regex::icase)
 	));
 	p.add("ignore_leading_the", yes_no(
 		ignore_leading_the, false