Added new RESTful API method to bind a local file to a url. Also added "dropper" directory into Social Engineering extension.

extensions/social_engineering/droppers/readme.txt

@@ -0,0 +1,9 @@
+This directory will contain the droppers (executables, JARs, browser extensions, etc..)
+that you want to have available on the BeEF server.
+
+For example, if you want to have bin.exe available at http://beefserver/bin.exe,
+use the following RESTful API call:
+
+curl -H "Content-Type: application/json; charset=UTF-8" -d
+'{"mount":"/bin.exe", "local_file":"/extensions/social_engineering/droppers/bin.exe"}'
+ -X POST http://beefserver/api/server/bind?token=<token>