feat(exclude): reorganize exclude option

This option now support all possible exclusions:

 * query by default to true
 * paths as an array of regexp

lib/index.js

@@ -16,7 +16,9 @@ function cache (config = {}) {
   config.readCache = config.readCache || readCache
   config.serialize = config.serialize || serialize
 
-  config.exclude = config.exclude || []
+  config.exclude = config.exclude || {}
+  config.exclude.query = config.exclude.query || true
+  config.exclude.paths = config.exclude.paths || []
 
   if (config.log !== false) {
     config.log = typeof config.log === 'function' ? config.log : console.log.bind(console)
@@ -32,13 +34,13 @@ function cache (config = {}) {
     }
 
     // do not cache request with query
-    if (req.url.match(/\?.*$/)) {
+    if (config.exclude.query && req.url.match(/\?.*$/)) {
       return null
     }
 
     let found = false
 
-    config.exclude.forEach(regexp => {
+    config.exclude.paths.forEach(regexp => {
       if (req.url.match(regexp)) {
         found = true
         return false