Add markdown syntax highlighting to README.md

README.md

@@ -45,20 +45,20 @@ formats:
 
 Client code shouldn't load these directly.  Instead, require 'stackvis' and use
 lookupReader and lookupWriter:
-
+```javascript
     var mod_stackvis = require('stackvis');
     var dtrace_reader = mod_stackvis.lookupReader('dtrace')
     var collapsed_writer = mod_stackvis.lookupWriter('collapsed');
-
+```
 The main operation is translating from one representation to another (e.g.,
 DTrace output to a flame graph) using pipeStacks() (which requires a Bunyan
 logger):
-
+```javascript
     var mod_bunyan = require('bunyan');
     var log = new mod_bunyan({ 'name': 'mytool', 'stream': process.stderr });
     mod_stackvis.pipeStacks(log, process.stdin, dtrace_reader, collapsed_writer,
         process.stdout, function () { console.error('translation finished'); });
-
+```
 This example instantiates a new dtrace_reader to read DTrace output from
 process.stdin and then emits the result in collapsed form to process.stdout
 through the collapsed_writer.