Omit files and print only match options added

These are essential for using the tool for scripting purposes.

src/config.rs

@@ -7,6 +7,8 @@ pub struct Config {
     pub ignore_case: bool,
     pub path: String,
     pub use_gitignore: bool,
+    pub omit_filenames: bool,
+    pub match_only: bool,
 }
 
 impl Config {
@@ -36,6 +38,16 @@ impl Config {
                     .long("no-gitignore")
                     .help("Include results that are specified in .gitignore"),
             )
+            .arg(
+                Arg::with_name("omit filenames")
+                    .short("h")
+                    .help("Omit file names in results"),
+            )
+            .arg(
+                Arg::with_name("only match")
+                    .short("o")
+                    .help("Only print matched text")
+            )
             .get_matches();
 
         Config {
@@ -43,6 +55,8 @@ impl Config {
             ignore_case: matches.is_present("ignore case"),
             path: String::from(matches.value_of("path").unwrap()),
             use_gitignore: !matches.is_present("gitignore"),
+            omit_filenames: matches.is_present("omit filenames"),
+            match_only: matches.is_present("only match"),
         }
     }
 }

src/printer.rs

@@ -43,15 +43,21 @@ impl<'a> Printer for SimplePrinter<'a> {
 
 impl<'a> SimplePrinter<'a> {
     fn print_file_name(&self) {
-        println!("{}:", self.file_match.file_name);
+        if !self.config.omit_filenames {
+            println!("{}:", self.file_match.file_name);
+        }
     }
 
     fn print_linenumber(&self, mat: &Match) {
-        print!("{}: ", mat.line_number);
+        if !self.config.omit_filenames {
+            print!("{}: ", mat.line_number);
+        }
     }
 
     fn print_first_part_of_line(&self, mat: &Match, current_position: usize, match_start: usize) {
-        print!("{}", mat.text.get(current_position..match_start).unwrap());
+        if !self.config.match_only {
+            print!("{}", mat.text.get(current_position..match_start).unwrap());
+        }
     }
 
     fn print_match(&self, mat: &Match, index: &MatchIndex) {
@@ -59,7 +65,11 @@ impl<'a> SimplePrinter<'a> {
     }
 
     fn print_end_of_line(&self, mat: &Match, index: &MatchIndex) {
-        println!("{}", mat.text.get(index.end..mat.text.len()).unwrap());
+        if !self.config.match_only {
+            println!("{}", mat.text.get(index.end..mat.text.len()).unwrap());
+        } else {
+            println!();
+        }
     }
 }